diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog for `in-other-words`
 
+## 0.2.1.0 (2021-11-05)
+### Non-breaking Changes
+* Added `hoistSteps`
+* Added `threadBaseControlViaUnlift`
+* GHC 9.0.1 compatiblity (thanks @berberman!)
+
 ## 0.2.0.0 (2021-01-30)
 ### Breaking Changes
 * `-Fast` interpretations of every continuation-related effect have been removed due
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -3,6 +3,7 @@
 [![build GHC 8.6](https://github.com/KingoftheHomeless/in-other-words/workflows/build%20GHC%208.6/badge.svg)](https://github.com/KingoftheHomeless/in-other-words/actions?query=workflow%3A%22build+GHC+8.6%22)
 [![build GHC 8.8](https://github.com/KingoftheHomeless/in-other-words/workflows/build%20GHC%208.8/badge.svg)](https://github.com/KingoftheHomeless/in-other-words/actions?query=workflow%3A%22build+GHC+8.8%22)
 [![build GHC 8.10](https://github.com/KingoftheHomeless/in-other-words/workflows/build%20GHC%208.10/badge.svg)](https://github.com/KingoftheHomeless/in-other-words/actions?query=workflow%3A%22build+GHC+8.10%22)
+[![build GHC 9.0.1](https://github.com/KingoftheHomeless/in-other-words/workflows/build%20GHC%209.0.1/badge.svg)](https://github.com/KingoftheHomeless/in-other-words/actions?query=workflow%3A%22build+GHC+9.0.1%22)
 
 - [Overview][]
 - [Features][]
diff --git a/in-other-words.cabal b/in-other-words.cabal
--- a/in-other-words.cabal
+++ b/in-other-words.cabal
@@ -1,13 +1,13 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.33.0.
+-- This file has been generated from package.yaml by hpack version 0.34.4.
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 94e61819ea6e924b216d8fa7fe755ab80100afa6a3ebf73d3da409a983481ce9
+-- hash: 63c053f88fc44761f95d97eedcd3be8a6130b0202778be539bab361549d74523
 
 name:           in-other-words
-version:        0.2.0.0
+version:        0.2.1.0
 synopsis:       A higher-order effect system where the sky's the limit
 description:    A low-boilerplate effect system with easy higher-order effects and very high expressive power
 category:       Control
@@ -109,15 +109,35 @@
       Paths_in_other_words
   hs-source-dirs:
       src
-  default-extensions: BangPatterns ConstraintKinds DataKinds DerivingStrategies EmptyCase FlexibleContexts FlexibleInstances FunctionalDependencies GADTs GeneralizedNewtypeDeriving LambdaCase PolyKinds QuantifiedConstraints RankNTypes ScopedTypeVariables StandaloneDeriving TypeApplications TypeOperators TypeFamilies UndecidableInstances
+  default-extensions:
+      BangPatterns
+      ConstraintKinds
+      DataKinds
+      DerivingStrategies
+      EmptyCase
+      FlexibleContexts
+      FlexibleInstances
+      FunctionalDependencies
+      GADTs
+      GeneralizedNewtypeDeriving
+      LambdaCase
+      PolyKinds
+      QuantifiedConstraints
+      RankNTypes
+      ScopedTypeVariables
+      StandaloneDeriving
+      TypeApplications
+      TypeOperators
+      TypeFamilies
+      UndecidableInstances
   ghc-options: -Wall -haddock
   build-depends:
-      async >=2.2 && <2.3
+      async ==2.2.*
     , base >=4.7 && <5
-    , exceptions >=0.10 && <0.11
-    , monad-control >=1.0 && <1.1
-    , mtl >=2.2 && <2.3
-    , stm >=2.5 && <2.6
+    , exceptions ==0.10.*
+    , monad-control ==1.0.*
+    , mtl ==2.2.*
+    , stm ==2.5.*
     , transformers >=0.5.6 && <0.6
     , transformers-base >=0.4.5 && <0.5
   default-language: Haskell2010
@@ -134,19 +154,39 @@
       Paths_in_other_words
   hs-source-dirs:
       test
-  default-extensions: BangPatterns ConstraintKinds DataKinds DerivingStrategies EmptyCase FlexibleContexts FlexibleInstances FunctionalDependencies GADTs GeneralizedNewtypeDeriving LambdaCase PolyKinds QuantifiedConstraints RankNTypes ScopedTypeVariables StandaloneDeriving TypeApplications TypeOperators TypeFamilies UndecidableInstances
+  default-extensions:
+      BangPatterns
+      ConstraintKinds
+      DataKinds
+      DerivingStrategies
+      EmptyCase
+      FlexibleContexts
+      FlexibleInstances
+      FunctionalDependencies
+      GADTs
+      GeneralizedNewtypeDeriving
+      LambdaCase
+      PolyKinds
+      QuantifiedConstraints
+      RankNTypes
+      ScopedTypeVariables
+      StandaloneDeriving
+      TypeApplications
+      TypeOperators
+      TypeFamilies
+      UndecidableInstances
   ghc-options: -threaded -rtsopts -with-rtsopts=-N -O0
   build-tool-depends:
       hspec-discover:hspec-discover >=2.0
   build-depends:
-      async >=2.2 && <2.3
+      async ==2.2.*
     , base >=4.7 && <5
-    , exceptions >=0.10 && <0.11
+    , exceptions ==0.10.*
     , hspec >=2.6.0 && <3
     , in-other-words
-    , monad-control >=1.0 && <1.1
-    , mtl >=2.2 && <2.3
-    , stm >=2.5 && <2.6
+    , monad-control ==1.0.*
+    , mtl ==2.2.*
+    , stm ==2.5.*
     , transformers >=0.5.6 && <0.6
     , transformers-base >=0.4.5 && <0.5
   default-language: Haskell2010
diff --git a/src/Control/Effect/BaseControl.hs b/src/Control/Effect/BaseControl.hs
--- a/src/Control/Effect/BaseControl.hs
+++ b/src/Control/Effect/BaseControl.hs
@@ -17,6 +17,7 @@
 
    -- * Threading utilities
   , threadBaseControlViaClass
+  , threadBaseControlViaUnlift
 
     -- * Combinators for 'Algebra's
     -- Intended to be used for custom 'Carrier' instances when
@@ -40,6 +41,7 @@
 import Control.Effect.Type.Internal.BaseControl
 import Control.Effect.Internal.BaseControl
 import Control.Effect.Internal.Itself
+import Control.Effect.Type.Unlift
 
 import Control.Effect.Internal.Utils
 
diff --git a/src/Control/Effect/Bracket.hs b/src/Control/Effect/Bracket.hs
--- a/src/Control/Effect/Bracket.hs
+++ b/src/Control/Effect/Bracket.hs
@@ -103,7 +103,7 @@
 type BracketToIOC = InterpretPrimC BracketToIOH Bracket
 
 
--- | Run a 'Bracket' by effect that protects against
+-- | Run a 'Bracket' effect that protects against
 -- any abortive computation of any effect, as well
 -- as any IO exceptions and asynchronous exceptions.
 --
@@ -131,7 +131,7 @@
 
 type BracketToIOUnsafeC = InterpretPrimC BracketToIOUnsafeH Bracket
 
--- | Run a 'Bracket' by effect that protects against
+-- | Run a 'Bracket' effect that protects against
 -- any abortive computation of any effect, as well
 -- as any IO exceptions and asynchronous exceptions.
 --
diff --git a/src/Control/Effect/Carrier/Internal/Interpret.hs b/src/Control/Effect/Carrier/Internal/Interpret.hs
--- a/src/Control/Effect/Carrier/Internal/Interpret.hs
+++ b/src/Control/Effect/Carrier/Internal/Interpret.hs
@@ -45,7 +45,7 @@
 instance (Carrier m, r ~ Derivs m, p ~ Prims m)
       => Reifies (CarrierReform m)
                  (ReifiedReformulation r p m) where
-  reflect = ReifiedReformulation reformulate
+  reflect = ReifiedReformulation $ \n alg -> reformulate n alg
   {-# INLINE reflect #-}
 
 
@@ -280,14 +280,16 @@
 instance ( RepresentationalEff e
          , Carrier m
          , Reifies s (ReifiedHandler e m)
-         ) => Handler (ViaReifiedH s) e m where
+         )
+        => Handler (ViaReifiedH s) e m where
   effHandler = getReifiedHandler (reflect @s)
   {-# INLINE effHandler #-}
 
 instance ( RepresentationalEff e
          , Carrier m
          , Reifies s (ReifiedPrimHandler e m)
-         ) => PrimHandler (ViaReifiedH s) e m where
+         )
+      => PrimHandler (ViaReifiedH s) e m where
   effPrimHandler = getReifiedPrimHandler (reflect @s)
   {-# INLINE effPrimHandler #-}
 
diff --git a/src/Control/Effect/Carrier/Internal/Stepped.hs b/src/Control/Effect/Carrier/Internal/Stepped.hs
--- a/src/Control/Effect/Carrier/Internal/Stepped.hs
+++ b/src/Control/Effect/Carrier/Internal/Stepped.hs
@@ -95,6 +95,10 @@
 liftSteps (Done a) = Done a
 liftSteps (More e c) = More e (lift . fmap liftSteps . c)
 
+hoistSteps :: Functor n => (forall x. m x -> n x) -> Steps e m a -> Steps e n a
+hoistSteps _ (Done a) = Done a
+hoistSteps n (More e c) = More e (fmap (hoistSteps n) . n . c)
+
 -- | Execute all the steps of a computation.
 unsteps :: forall e m a
          . ( FirstOrder e
diff --git a/src/Control/Effect/Error.hs b/src/Control/Effect/Error.hs
--- a/src/Control/Effect/Error.hs
+++ b/src/Control/Effect/Error.hs
@@ -76,7 +76,7 @@
 
 
 throw :: Eff (Throw e) m => e -> m a
-throw = send . Throw
+throw = send .# Throw
 {-# INLINE throw #-}
 
 catch :: Eff (Catch e) m => m a -> (e -> m a) -> m a
diff --git a/src/Control/Effect/Stepped.hs b/src/Control/Effect/Stepped.hs
--- a/src/Control/Effect/Stepped.hs
+++ b/src/Control/Effect/Stepped.hs
@@ -1,14 +1,15 @@
-module Control.Effect.Stepped
-  ( SteppedC
-  , Steps(..)
-  , steps
-  , unsteps
-  , liftSteps
-
-  , FirstOrder
-
-    -- Threading constraints
-  , SteppedThreads
-  ) where
-
-import Control.Effect.Carrier.Internal.Stepped
+module Control.Effect.Stepped
+  ( SteppedC
+  , Steps(..)
+  , steps
+  , unsteps
+  , liftSteps
+  , hoistSteps
+
+  , FirstOrder
+
+    -- Threading constraints
+  , SteppedThreads
+  ) where
+
+import Control.Effect.Carrier.Internal.Stepped
diff --git a/src/Control/Effect/Type/Unlift.hs b/src/Control/Effect/Type/Unlift.hs
--- a/src/Control/Effect/Type/Unlift.hs
+++ b/src/Control/Effect/Type/Unlift.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE MagicHash #-}
 {-# OPTIONS_HADDOCK not-home #-}
 module Control.Effect.Type.Unlift
  ( -- * Effects
@@ -5,6 +6,7 @@
 
    -- Threading utilities
  , threadUnliftViaClass
+ , threadBaseControlViaUnlift
 
    -- 'MonadBaseControlPure' and 'MonadTransControlPure'
  , MonadBaseControlPure
@@ -14,7 +16,13 @@
  , unliftT
  ) where
 
+import GHC.Exts (Proxy#, proxy#)
+import Data.Coerce
 import Control.Effect.Internal.Union
+import Control.Effect.Internal.Utils
+import Control.Effect.Type.Internal.BaseControl
+import Control.Monad.Base
+import Control.Monad.Trans
 import Control.Monad.Trans.Control
 import Control.Monad.Trans.Reader
 
@@ -88,8 +96,9 @@
 newtype Unlift b :: Effect where
   Unlift :: forall b m a. ((forall x. m x -> b x) -> b a) -> Unlift b m a
 
--- | A valid definition of 'threadEff' for a @'ThreadsEff' ('Unlift' b) t@ instance,
--- given that @t@ is a 'MonadTransControl' where @'StT' t a ~ a@ holds for all @a@.
+-- | A valid definition of 'threadEff' for a @'ThreadsEff' ('Unlift' b) t@
+-- instance, given that @t@ is a 'MonadTransControl' where @'StT' t a ~ a@ holds
+-- for all @a@.
 threadUnliftViaClass :: forall b t m a
                       . (MonadTransControlPure t, Monad m)
                      => (forall x. Unlift b m x -> m x)
@@ -97,6 +106,47 @@
 threadUnliftViaClass alg (Unlift main) = unliftT $ \lowerT ->
   alg $ Unlift $ \lowerM -> main (lowerM . lowerT)
 {-# INLINE threadUnliftViaClass #-}
+
+-- | A valid definition of 'threadEff' for a @'ThreadsEff' ('BaseControl' b) t@
+-- instance, given that @t@ threads @'Unlift' z@ for any 'Monad' @z@.
+threadBaseControlViaUnlift :: forall b t m a
+                            . ( Monad m
+                              , MonadTrans t
+                              , forall z. Monad z => Monad (t z)
+                              ,    forall z
+                                 . Coercible z m
+                                => Coercible (t z) (t m)
+                              , forall z. Monad z => ThreadsEff t (Unlift z)
+                              )
+                           => (forall x. BaseControl b m x -> m x)
+                           -> BaseControl b (t m) a -> t m a
+threadBaseControlViaUnlift alg (GainBaseControl main) =
+    lift $ alg $ GainBaseControl $ \(_ :: Proxy# z) ->
+      main (proxy# :: Proxy# (Unlifted t z))
+{-# INLINE threadBaseControlViaUnlift #-}
+
+newtype Unlifted t m a = Unlifted { unUnlifted :: t m a }
+  deriving (Functor, Applicative, Monad)
+  deriving MonadTrans
+
+instance (MonadBase b m, MonadTrans t, Monad (t m))
+      => MonadBase b (Unlifted t m) where
+  liftBase = lift . liftBase
+  {-# INLINE liftBase #-}
+
+instance (MonadBaseControl b m, MonadTrans t, ThreadsEff t (Unlift m),
+          Monad (t m))
+      => MonadBaseControl b (Unlifted t m) where
+  type StM (Unlifted t m) a = StM m a
+
+  liftBaseWith main =
+    Unlifted $ threadEff (\(Unlift main') -> main' id) $ Unlift $ \lower ->
+      liftBaseWith $ \run_it -> main $ run_it . lower .# unUnlifted
+  {-# INLINE liftBaseWith #-}
+
+  restoreM = Unlifted #. lift . restoreM
+  {-# INLINE restoreM #-}
+
 
 instance ThreadsEff (ReaderT i) (Unlift b) where
   threadEff alg (Unlift main) = ReaderT $ \s ->