diff --git a/beacon_node/beacon_chain/src/block_processing.rs b/beacon_node/beacon_chain/src/block_processing.rs
index f99958dfbd..32670f51d2 100644
--- a/beacon_node/beacon_chain/src/block_processing.rs
+++ b/beacon_node/beacon_chain/src/block_processing.rs
@@ -8,16 +8,23 @@ use types::{
 };
 
 #[derive(Debug, PartialEq)]
-pub enum Outcome {
-    FutureSlot,
+pub enum ValidBlock {
     Processed,
-    NewCanonicalBlock,
-    NewReorgBlock,
-    NewForkBlock,
+}
+
+#[derive(Debug, PartialEq)]
+pub enum InvalidBlock {
+    FutureSlot,
     StateTransitionFailed(TransitionError),
     StateRootMismatch,
 }
 
+#[derive(Debug, PartialEq)]
+pub enum Outcome {
+    ValidBlock(ValidBlock),
+    InvalidBlock(InvalidBlock),
+}
+
 #[derive(Debug, PartialEq)]
 pub enum Error {
     DBError(String),
@@ -70,7 +77,7 @@ where
 
         // Block from future slots (i.e., greater than the present slot) should not be processed.
         if block.slot() > present_slot {
-            return Ok(Outcome::FutureSlot);
+            return Ok(Outcome::InvalidBlock(InvalidBlock::FutureSlot));
         }
 
         let parent_block_root = block.parent_root();
@@ -80,7 +87,8 @@ where
             .get_reader(&parent_block_root)?
             .ok_or(Error::MissingParentBlock(parent_block_root))?;
 
-        let parent_state_root = parent_block.parent_root();
+        let parent_state_root = parent_block.state_root();
+
         let parent_state = self
             .state_store
             .get_reader(&parent_state_root)?
@@ -90,13 +98,17 @@ where
 
         let state = match self.state_transition(parent_state, &block) {
             Ok(state) => state,
-            Err(error) => return Ok(Outcome::StateTransitionFailed(error)),
+            Err(error) => {
+                return Ok(Outcome::InvalidBlock(InvalidBlock::StateTransitionFailed(
+                    error,
+                )))
+            }
         };
 
         let state_root = state.canonical_root();
 
         if block.state_root != state_root {
-            return Ok(Outcome::StateRootMismatch);
+            return Ok(Outcome::InvalidBlock(InvalidBlock::StateRootMismatch));
         }
 
         // Store the block and state.
@@ -119,7 +131,7 @@ where
         }
 
         // The block was sucessfully processed.
-        Ok(Outcome::Processed)
+        Ok(Outcome::ValidBlock(ValidBlock::Processed))
     }
 }
 
diff --git a/beacon_node/beacon_chain/src/finalized_head.rs b/beacon_node/beacon_chain/src/finalized_head.rs
new file mode 100644
index 0000000000..28c883b4cf
--- /dev/null
+++ b/beacon_node/beacon_chain/src/finalized_head.rs
@@ -0,0 +1,34 @@
+use crate::{BeaconChain, CheckPoint, ClientDB, SlotClock};
+use std::sync::RwLockReadGuard;
+use types::{BeaconBlock, BeaconState, Hash256};
+
+impl<T, U> BeaconChain<T, U>
+where
+    T: ClientDB,
+    U: SlotClock,
+{
+    pub fn update_finalized_head(
+        &self,
+        new_beacon_block: BeaconBlock,
+        new_beacon_block_root: Hash256,
+        new_beacon_state: BeaconState,
+        new_beacon_state_root: Hash256,
+    ) {
+        let mut finalized_head = self
+            .finalized_head
+            .write()
+            .expect("CRITICAL: finalized_head poisioned.");
+        finalized_head.update(
+            new_beacon_block,
+            new_beacon_block_root,
+            new_beacon_state,
+            new_beacon_state_root,
+        );
+    }
+
+    pub fn finalized_head(&self) -> RwLockReadGuard<CheckPoint> {
+        self.finalized_head
+            .read()
+            .expect("CRITICAL: finalized_head poisioned.")
+    }
+}
diff --git a/beacon_node/beacon_chain/src/lib.rs b/beacon_node/beacon_chain/src/lib.rs
index b52dfdd73e..8ae6d0f904 100644
--- a/beacon_node/beacon_chain/src/lib.rs
+++ b/beacon_node/beacon_chain/src/lib.rs
@@ -1,8 +1,9 @@
 mod attestation_targets;
 mod block_graph;
-mod block_processing;
+pub mod block_processing;
 pub mod block_production;
 mod canonical_head;
+mod finalized_head;
 mod info;
 mod lmd_ghost;
 mod state_transition;
@@ -17,9 +18,8 @@ use genesis::{genesis_beacon_block, genesis_beacon_state, GenesisError};
 use slot_clock::SlotClock;
 use spec::ChainSpec;
 use ssz::ssz_encode;
-use std::collections::{HashMap, HashSet};
 use std::sync::{Arc, RwLock};
-use types::{BeaconBlock, BeaconState, Hash256, PublicKey};
+use types::{BeaconBlock, BeaconState, Hash256};
 
 pub use self::block_processing::Outcome as BlockProcessingOutcome;
 
diff --git a/beacon_node/beacon_chain/src/lmd_ghost.rs b/beacon_node/beacon_chain/src/lmd_ghost.rs
index e4aaa34835..6116834bb4 100644
--- a/beacon_node/beacon_chain/src/lmd_ghost.rs
+++ b/beacon_node/beacon_chain/src/lmd_ghost.rs
@@ -32,7 +32,31 @@ where
     U: SlotClock,
     Error: From<<U as SlotClock>::Error>,
 {
-    pub fn slow_lmd_ghost(&mut self, start_hash: &Hash256) -> Result<Hash256, Error> {
+    pub fn fork_choice(&self) -> Result<(), Error> {
+        let present_head = &self.finalized_head().beacon_block_root;
+
+        let new_head = self.slow_lmd_ghost(&self.finalized_head().beacon_block_root)?;
+
+        if new_head != *present_head {
+            let block = self
+                .block_store
+                .get_deserialized(&new_head)?
+                .ok_or_else(|| Error::MissingBeaconBlock(new_head))?;
+            let block_root = block.canonical_root();
+
+            let state = self
+                .state_store
+                .get_deserialized(&block.state_root)?
+                .ok_or_else(|| Error::MissingBeaconState(block.state_root))?;
+            let state_root = state.canonical_root();
+
+            self.update_canonical_head(block, block_root, state, state_root);
+        }
+
+        Ok(())
+    }
+
+    pub fn slow_lmd_ghost(&self, start_hash: &Hash256) -> Result<Hash256, Error> {
         let start = self
             .block_store
             .get_reader(&start_hash)?
diff --git a/beacon_node/beacon_chain/tests/chain.rs b/beacon_node/beacon_chain/tests/chain.rs
index 3c0a9b8f92..52d001eed3 100644
--- a/beacon_node/beacon_chain/tests/chain.rs
+++ b/beacon_node/beacon_chain/tests/chain.rs
@@ -20,8 +20,9 @@ fn rig_can_generate_validators() {
     let validators = generate_validators(2, &chain);
     chain.spec = inject_validators_into_spec(chain.spec.clone(), &validators[..]);
     */
-    let mut rig = TestRig::new(ChainSpec::foundation());
-    rig.generate_validators(2);
+    let validator_count = 2;
+    let mut rig = TestRig::new(ChainSpec::foundation(), validator_count);
+    rig.produce_next_slot();
 }
 
 /*
diff --git a/beacon_node/beacon_chain/tests/utils/direct_beacon_node.rs b/beacon_node/beacon_chain/tests/utils/direct_beacon_node.rs
index 130a4d1360..9fcd7c2862 100644
--- a/beacon_node/beacon_chain/tests/utils/direct_beacon_node.rs
+++ b/beacon_node/beacon_chain/tests/utils/direct_beacon_node.rs
@@ -1,22 +1,27 @@
+use beacon_chain::block_processing::{Error as ProcessingError, Outcome as ProcessingOutcome};
 use beacon_chain::{block_production::Error as BlockProductionError, BeaconChain};
-use block_producer::{BeaconNode as BeaconBlockNode, BeaconNodeError as BeaconBlockNodeError};
+use block_producer::{
+    BeaconNode as BeaconBlockNode, BeaconNodeError as BeaconBlockNodeError, PublishOutcome,
+};
 use db::ClientDB;
 use slot_clock::SlotClock;
+use std::sync::Arc;
 use types::{BeaconBlock, PublicKey, Signature};
 
-pub struct DirectBeaconNode<'a, T: ClientDB, U: SlotClock> {
-    beacon_chain: &'a BeaconChain<T, U>,
+pub struct DirectBeaconNode<T: ClientDB, U: SlotClock> {
+    beacon_chain: Arc<BeaconChain<T, U>>,
 }
 
-impl<'a, T: ClientDB, U: SlotClock> DirectBeaconNode<'a, T, U> {
-    pub fn new(beacon_chain: &'a BeaconChain<T, U>) -> Self {
+impl<T: ClientDB, U: SlotClock> DirectBeaconNode<T, U> {
+    pub fn new(beacon_chain: Arc<BeaconChain<T, U>>) -> Self {
         Self { beacon_chain }
     }
 }
 
-impl<'a, T: ClientDB, U: SlotClock> BeaconBlockNode for DirectBeaconNode<'a, T, U>
+impl<T: ClientDB, U: SlotClock> BeaconBlockNode for DirectBeaconNode<T, U>
 where
     BlockProductionError: From<<U>::Error>,
+    ProcessingError: From<<U as SlotClock>::Error>,
 {
     fn proposer_nonce(&self, pubkey: &PublicKey) -> Result<u64, BeaconBlockNodeError> {
         let validator_index = self
@@ -51,8 +56,16 @@ where {
         }
     }
 
-    /// Returns the value specified by the `set_next_publish_result`.
-    fn publish_beacon_block(&self, block: BeaconBlock) -> Result<bool, BeaconBlockNodeError> {
-        Err(BeaconBlockNodeError::DecodeFailure)
+    fn publish_beacon_block(
+        &self,
+        block: BeaconBlock,
+    ) -> Result<PublishOutcome, BeaconBlockNodeError> {
+        match self.beacon_chain.process_block(block) {
+            Ok(ProcessingOutcome::ValidBlock(_)) => Ok(PublishOutcome::ValidBlock),
+            Ok(ProcessingOutcome::InvalidBlock(reason)) => {
+                Ok(PublishOutcome::InvalidBlock(format!("{:?}", reason)))
+            }
+            Err(error) => Err(BeaconBlockNodeError::RemoteFailure(format!("{:?}", error))),
+        }
     }
 }
diff --git a/beacon_node/beacon_chain/tests/utils/direct_duties.rs b/beacon_node/beacon_chain/tests/utils/direct_duties.rs
index 75177ac149..ff2cd7223f 100644
--- a/beacon_node/beacon_chain/tests/utils/direct_duties.rs
+++ b/beacon_node/beacon_chain/tests/utils/direct_duties.rs
@@ -2,15 +2,16 @@ use beacon_chain::{block_production::Error as BlockProductionError, BeaconChain}
 use block_producer::{DutiesReader, DutiesReaderError};
 use db::ClientDB;
 use slot_clock::SlotClock;
+use std::sync::Arc;
 use types::PublicKey;
 
-pub struct DirectDuties<'a, T: ClientDB, U: SlotClock> {
-    beacon_chain: &'a BeaconChain<T, U>,
+pub struct DirectDuties<T: ClientDB, U: SlotClock> {
+    beacon_chain: Arc<BeaconChain<T, U>>,
     pubkey: PublicKey,
 }
 
-impl<'a, T: ClientDB, U: SlotClock> DirectDuties<'a, T, U> {
-    pub fn new(pubkey: PublicKey, beacon_chain: &'a BeaconChain<T, U>) -> Self {
+impl<T: ClientDB, U: SlotClock> DirectDuties<T, U> {
+    pub fn new(pubkey: PublicKey, beacon_chain: Arc<BeaconChain<T, U>>) -> Self {
         Self {
             beacon_chain,
             pubkey,
@@ -18,11 +19,11 @@ impl<'a, T: ClientDB, U: SlotClock> DirectDuties<'a, T, U> {
     }
 }
 
-impl<'a, T: ClientDB, U: SlotClock> DutiesReader for DirectDuties<'a, T, U>
+impl<T: ClientDB, U: SlotClock> DutiesReader for DirectDuties<T, U>
 where
     BlockProductionError: From<<U>::Error>,
 {
-    fn is_block_production_slot(&self, _epoch: u64, slot: u64) -> Result<bool, DutiesReaderError> {
+    fn is_block_production_slot(&self, slot: u64) -> Result<bool, DutiesReaderError> {
         let validator_index = self
             .beacon_chain
             .validator_index(&self.pubkey)
diff --git a/beacon_node/beacon_chain/tests/utils/test_rig.rs b/beacon_node/beacon_chain/tests/utils/test_rig.rs
index 0bdf0a36bb..7bd494b23a 100644
--- a/beacon_node/beacon_chain/tests/utils/test_rig.rs
+++ b/beacon_node/beacon_chain/tests/utils/test_rig.rs
@@ -11,75 +11,77 @@ use spec::ChainSpec;
 use std::sync::{Arc, RwLock};
 use types::{Keypair, Validator};
 
-pub struct TestRig<'a> {
+pub struct TestRig {
     db: Arc<MemoryDB>,
-    beacon_chain: BeaconChain<MemoryDB, TestingSlotClock>,
+    beacon_chain: Arc<BeaconChain<MemoryDB, TestingSlotClock>>,
     block_store: Arc<BeaconBlockStore<MemoryDB>>,
     state_store: Arc<BeaconStateStore<MemoryDB>>,
-    validators: Vec<TestValidator<'a>>,
+    validators: Vec<TestValidator>,
 }
 
-impl<'a> TestRig<'a> {
-    pub fn new(spec: ChainSpec) -> Self {
+impl TestRig {
+    pub fn new(mut spec: ChainSpec, validator_count: usize) -> Self {
         let db = Arc::new(MemoryDB::open());
         let block_store = Arc::new(BeaconBlockStore::new(db.clone()));
         let state_store = Arc::new(BeaconStateStore::new(db.clone()));
 
         let slot_clock = TestingSlotClock::new(0);
 
-        let mut beacon_chain =
-            BeaconChain::genesis(state_store.clone(), block_store.clone(), slot_clock, spec)
-                .unwrap();
+        // Remove the validators present in the spec (if any).
+        spec.initial_validators = Vec::with_capacity(validator_count);
+        spec.initial_balances = Vec::with_capacity(validator_count);
 
-        /*
-        let validators = generate_validators(validator_count, &beacon_chain);
-        beacon_chain.spec = inject_validators_into_spec(beacon_chain.spec.clone(), &validators[..]);
-        */
+        // Insert `validator_count` new `Validator` records into the spec, retaining the keypairs
+        // for later user.
+        let mut keypairs = Vec::with_capacity(validator_count);
+        for _ in 0..validator_count {
+            let keypair = Keypair::random();
+
+            spec.initial_validators.push(Validator {
+                pubkey: keypair.pk.clone(),
+                ..std::default::Default::default()
+            });
+            spec.initial_balances.push(32_000_000_000); // 32 ETH
+
+            keypairs.push(keypair);
+        }
+
+        // Create the Beacon Chain
+        let beacon_chain = Arc::new(
+            BeaconChain::genesis(state_store.clone(), block_store.clone(), slot_clock, spec)
+                .unwrap(),
+        );
+
+        // Spawn the test validator instances.
+        let mut validators = Vec::with_capacity(validator_count);
+        for keypair in keypairs {
+            validators.push(TestValidator::new(keypair.clone(), beacon_chain.clone()));
+        }
 
         Self {
             db,
             beacon_chain,
             block_store,
             state_store,
-            validators: vec![],
+            validators,
         }
     }
 
-    pub fn generate_validators(&'a mut self, validator_count: usize) {
-        self.validators = Vec::with_capacity(validator_count);
-        for _ in 0..validator_count {
-            self.validators.push(TestValidator::new(&self.beacon_chain));
-        }
-        self.beacon_chain.spec =
-            inject_validators_into_spec(self.beacon_chain.spec.clone(), &self.validators[..]);
-    }
-
-    pub fn process_next_slot(&mut self) {
+    pub fn produce_next_slot(&mut self) {
         let slot = self
             .beacon_chain
             .present_slot()
             .expect("Unable to determine slot.")
             + 1;
+
         self.beacon_chain.slot_clock.set_slot(slot);
 
-        let block_proposer = self
+        let proposer = self
             .beacon_chain
             .block_proposer(slot)
             .expect("Unable to determine proposer.");
 
-        let validator = self
-            .validators
-            .get(block_proposer)
-            .expect("Block proposer unknown");
+        self.validators[proposer].set_slot(slot);
+        self.validators[proposer].produce_block().unwrap();
     }
 }
-
-fn inject_validators_into_spec(mut spec: ChainSpec, validators: &[TestValidator]) -> ChainSpec {
-    spec.initial_validators = Vec::with_capacity(validators.len());
-    spec.initial_balances = Vec::with_capacity(validators.len());
-    for validator in validators {
-        spec.initial_validators.push(validator.validator_record());
-        spec.initial_balances.push(32_000_000_000); // 32 ETH
-    }
-    spec
-}
diff --git a/beacon_node/beacon_chain/tests/utils/validator.rs b/beacon_node/beacon_chain/tests/utils/validator.rs
index a6a348dced..755ea51d10 100644
--- a/beacon_node/beacon_chain/tests/utils/validator.rs
+++ b/beacon_node/beacon_chain/tests/utils/validator.rs
@@ -1,36 +1,46 @@
 use super::{DirectBeaconNode, DirectDuties};
 use beacon_chain::BeaconChain;
 #[cfg(test)]
-use block_producer::{test_utils::TestSigner, BlockProducer};
+use block_producer::{test_utils::TestSigner, BlockProducer, Error as PollError};
 use db::MemoryDB;
 use slot_clock::TestingSlotClock;
 use spec::ChainSpec;
 use std::sync::{Arc, RwLock};
 use types::{Keypair, Validator};
 
-pub struct TestValidator<'a> {
+pub use block_producer::PollOutcome;
+
+#[derive(Debug, PartialEq)]
+pub enum ProduceError {
+    DidNotProduce(PollOutcome),
+    PollError(PollError),
+}
+
+pub struct TestValidator {
     block_producer: BlockProducer<
         TestingSlotClock,
-        DirectBeaconNode<'a, MemoryDB, TestingSlotClock>,
-        DirectDuties<'a, MemoryDB, TestingSlotClock>,
+        DirectBeaconNode<MemoryDB, TestingSlotClock>,
+        DirectDuties<MemoryDB, TestingSlotClock>,
         TestSigner,
     >,
     spec: Arc<ChainSpec>,
-    epoch_map: Arc<DirectDuties<'a, MemoryDB, TestingSlotClock>>,
+    epoch_map: Arc<DirectDuties<MemoryDB, TestingSlotClock>>,
     keypair: Keypair,
-    beacon_node: Arc<DirectBeaconNode<'a, MemoryDB, TestingSlotClock>>,
-    slot_clock: Arc<RwLock<TestingSlotClock>>,
+    beacon_node: Arc<DirectBeaconNode<MemoryDB, TestingSlotClock>>,
+    slot_clock: Arc<TestingSlotClock>,
     signer: Arc<TestSigner>,
 }
 
-impl<'a> TestValidator<'a> {
-    pub fn new(beacon_chain: &'a BeaconChain<MemoryDB, TestingSlotClock>) -> Self {
+impl TestValidator {
+    pub fn new(
+        keypair: Keypair,
+        beacon_chain: Arc<BeaconChain<MemoryDB, TestingSlotClock>>,
+    ) -> Self {
         let spec = Arc::new(ChainSpec::foundation());
-        let keypair = Keypair::random();
-        let slot_clock = Arc::new(RwLock::new(TestingSlotClock::new(0)));
+        let slot_clock = Arc::new(TestingSlotClock::new(0));
         let signer = Arc::new(TestSigner::new(keypair.clone()));
-        let beacon_node = Arc::new(DirectBeaconNode::new(beacon_chain));
-        let epoch_map = Arc::new(DirectDuties::new(keypair.pk.clone(), beacon_chain));
+        let beacon_node = Arc::new(DirectBeaconNode::new(beacon_chain.clone()));
+        let epoch_map = Arc::new(DirectDuties::new(keypair.pk.clone(), beacon_chain.clone()));
 
         let block_producer = BlockProducer::new(
             spec.clone(),
@@ -52,10 +62,15 @@ impl<'a> TestValidator<'a> {
         }
     }
 
-    pub fn validator_record(&self) -> Validator {
-        Validator {
-            pubkey: self.keypair.pk.clone(),
-            ..std::default::Default::default()
+    pub fn produce_block(&mut self) -> Result<PollOutcome, ProduceError> {
+        match self.block_producer.poll() {
+            Ok(PollOutcome::BlockProduced(slot)) => Ok(PollOutcome::BlockProduced(slot)),
+            Ok(outcome) => Err(ProduceError::DidNotProduce(outcome)),
+            Err(error) => Err(ProduceError::PollError(error)),
         }
     }
+
+    pub fn set_slot(&mut self, slot: u64) {
+        self.slot_clock.set_slot(slot)
+    }
 }