diff --git a/Cargo.toml b/Cargo.toml
index 65badc0e..335c1b9f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "roaring"
-version = "0.4.2"
+version = "0.5.0"
 authors = ["Wim Looman <wim@nemo157.com>"]
 description = "http://roaringbitmap.org : A better compressed bitset - pure Rust implementation "
 
diff --git a/src/cmp.rs b/src/bitmap/cmp.rs
similarity index 99%
rename from src/cmp.rs
rename to src/bitmap/cmp.rs
index 9b495163..09f89772 100644
--- a/src/cmp.rs
+++ b/src/bitmap/cmp.rs
@@ -2,7 +2,7 @@ use std::slice;
 use std::iter::Peekable;
 
 use RoaringBitmap;
-use container::Container;
+use super::container::Container;
 
 struct Pairs<'a>(Peekable<slice::Iter<'a, Container>>, Peekable<slice::Iter<'a, Container>>);
 
diff --git a/src/container.rs b/src/bitmap/container.rs
similarity index 98%
rename from src/container.rs
rename to src/bitmap/container.rs
index 7d8c7549..ea79fd45 100644
--- a/src/container.rs
+++ b/src/bitmap/container.rs
@@ -1,7 +1,7 @@
 use std::fmt;
 
-use util;
-use store::{ self, Store };
+use super::util;
+use super::store::{ self, Store };
 
 const ARRAY_LIMIT: u64 = 4096;
 
diff --git a/src/fmt.rs b/src/bitmap/fmt.rs
similarity index 100%
rename from src/fmt.rs
rename to src/bitmap/fmt.rs
diff --git a/src/inherent.rs b/src/bitmap/inherent.rs
similarity index 99%
rename from src/inherent.rs
rename to src/bitmap/inherent.rs
index a5e779cb..82078cc4 100644
--- a/src/inherent.rs
+++ b/src/bitmap/inherent.rs
@@ -1,7 +1,7 @@
 use RoaringBitmap;
 
-use util;
-use container::Container;
+use super::util;
+use super::container::Container;
 
 impl RoaringBitmap {
     /// Creates an empty `RoaringBitmap`.
diff --git a/src/iter.rs b/src/bitmap/iter.rs
similarity index 98%
rename from src/iter.rs
rename to src/bitmap/iter.rs
index 2ee1b25f..f8aec072 100644
--- a/src/iter.rs
+++ b/src/bitmap/iter.rs
@@ -3,7 +3,7 @@ use std::slice;
 use std::vec;
 
 use RoaringBitmap;
-use container::Container;
+use super::container::Container;
 
 /// An iterator for `RoaringBitmap`.
 pub struct Iter<'a> {
diff --git a/src/bitmap/mod.rs b/src/bitmap/mod.rs
new file mode 100644
index 00000000..aef5e0e4
--- /dev/null
+++ b/src/bitmap/mod.rs
@@ -0,0 +1,36 @@
+mod store;
+mod container;
+mod util;
+mod fmt;
+
+// Order of these modules matters as it determines the `impl` blocks order in
+// the docs
+mod inherent;
+mod iter;
+mod ops;
+mod cmp;
+mod serialization;
+
+pub use self::iter::Iter;
+pub use self::iter::IntoIter;
+
+/// A compressed bitmap using the [Roaring bitmap compression scheme](http://roaringbitmap.org).
+///
+/// # Examples
+///
+/// ```rust
+/// use roaring::RoaringBitmap;
+///
+/// let mut rb = RoaringBitmap::new();
+///
+/// // insert all primes less than 10
+/// rb.insert(2);
+/// rb.insert(3);
+/// rb.insert(5);
+/// rb.insert(7);
+/// println!("total bits set to true: {}", rb.len());
+/// ```
+#[derive(PartialEq, Clone)]
+pub struct RoaringBitmap {
+    containers: Vec<container::Container>,
+}
diff --git a/src/ops.rs b/src/bitmap/ops.rs
similarity index 100%
rename from src/ops.rs
rename to src/bitmap/ops.rs
diff --git a/src/serialization.rs b/src/bitmap/serialization.rs
similarity index 98%
rename from src/serialization.rs
rename to src/bitmap/serialization.rs
index fe041954..6a66a735 100644
--- a/src/serialization.rs
+++ b/src/bitmap/serialization.rs
@@ -2,8 +2,8 @@ use std::io;
 use byteorder::{ LittleEndian, ReadBytesExt, WriteBytesExt };
 
 use RoaringBitmap;
-use store::Store;
-use container::Container;
+use super::store::Store;
+use super::container::Container;
 
 const SERIAL_COOKIE_NO_RUNCONTAINER: u32 = 12346;
 const SERIAL_COOKIE: u16 = 12347;
diff --git a/src/store.rs b/src/bitmap/store.rs
similarity index 100%
rename from src/store.rs
rename to src/bitmap/store.rs
diff --git a/src/util.rs b/src/bitmap/util.rs
similarity index 100%
rename from src/util.rs
rename to src/bitmap/util.rs
diff --git a/src/lib.rs b/src/lib.rs
index f1387c4c..b76bc1f8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -14,43 +14,11 @@
 
 extern crate byteorder;
 
-mod store;
-mod container;
-mod util;
-mod fmt;
-
-// Order of these modules matters as it determines the `impl` blocks order in
-// the docs
-mod inherent;
-mod iter;
-mod ops;
-mod cmp;
-mod serialization;
-
-pub use iter::Iter;
+/// A compressed bitmap using the [Roaring bitmap compression scheme](http://roaringbitmap.org).
+pub mod bitmap;
 
 /// A compressed bitmap with u64 values.  Implemented as a `BTreeMap` of `RoaringBitmap`s.
-pub mod roaring_treemap;
-
-/// A compressed bitmap using the [Roaring bitmap compression scheme](http://roaringbitmap.org).
-///
-/// # Examples
-///
-/// ```rust
-/// use roaring::RoaringBitmap;
-///
-/// let mut rb = RoaringBitmap::new();
-///
-/// // insert all primes less than 10
-/// rb.insert(2);
-/// rb.insert(3);
-/// rb.insert(5);
-/// rb.insert(7);
-/// println!("total bits set to true: {}", rb.len());
-/// ```
-#[derive(PartialEq, Clone)]
-pub struct RoaringBitmap {
-    containers: Vec<container::Container>,
-}
+pub mod treemap;
 
-pub use roaring_treemap::RoaringTreemap;
+pub use bitmap::RoaringBitmap;
+pub use treemap::RoaringTreemap;
diff --git a/src/roaring_treemap/cmp.rs b/src/treemap/cmp.rs
similarity index 100%
rename from src/roaring_treemap/cmp.rs
rename to src/treemap/cmp.rs
diff --git a/src/roaring_treemap/fmt.rs b/src/treemap/fmt.rs
similarity index 100%
rename from src/roaring_treemap/fmt.rs
rename to src/treemap/fmt.rs
diff --git a/src/roaring_treemap/inherent.rs b/src/treemap/inherent.rs
similarity index 100%
rename from src/roaring_treemap/inherent.rs
rename to src/treemap/inherent.rs
diff --git a/src/roaring_treemap/iter.rs b/src/treemap/iter.rs
similarity index 98%
rename from src/roaring_treemap/iter.rs
rename to src/treemap/iter.rs
index 3125ff29..e313ed59 100644
--- a/src/roaring_treemap/iter.rs
+++ b/src/treemap/iter.rs
@@ -2,8 +2,8 @@ use std::collections::BTreeMap;
 use std::collections::btree_map;
 use std::iter::{self, FromIterator};
 
-use iter::Iter as Iter32;
-use iter::IntoIter as IntoIter32;
+use bitmap::Iter as Iter32;
+use bitmap::IntoIter as IntoIter32;
 use super::util;
 use RoaringBitmap;
 use RoaringTreemap;
diff --git a/src/roaring_treemap/mod.rs b/src/treemap/mod.rs
similarity index 94%
rename from src/roaring_treemap/mod.rs
rename to src/treemap/mod.rs
index 703f1d7e..79f045cd 100644
--- a/src/roaring_treemap/mod.rs
+++ b/src/treemap/mod.rs
@@ -11,7 +11,8 @@ mod iter;
 mod ops;
 mod cmp;
 
-pub use iter::{Iter, IntoIter};
+pub use self::iter::{Iter, IntoIter};
+
 /// A compressed bitmap with u64 values.
 /// Implemented as a `BTreeMap` of `RoaringBitmap`s.
 ///
diff --git a/src/roaring_treemap/ops.rs b/src/treemap/ops.rs
similarity index 100%
rename from src/roaring_treemap/ops.rs
rename to src/treemap/ops.rs
diff --git a/src/roaring_treemap/util.rs b/src/treemap/util.rs
similarity index 100%
rename from src/roaring_treemap/util.rs
rename to src/treemap/util.rs