diff --git a/doc.go b/doc.go
new file mode 100644
index 0000000..f2a98d5
--- /dev/null
+++ b/doc.go
@@ -0,0 +1,8 @@
+// Package ed25519 implements an elliptic.Curve interface on top of the twisted
+// Edwards curve -x^2 + y^2 = 1 + -(121665/121666)*x^2*y^2. This is better
+// known as the Edwards curve equivalent to curve25519, and is the curve used
+// by the Ed25519 signature scheme.
+//
+// Because of the Curve interface, this package takes input in affine (x,y)
+// pairs instead of the more standard compressed Edwards y.
+package ed25519
diff --git a/ed25519.go b/ed25519.go
index 3b4a5d4..ca3d7ec 100644
--- a/ed25519.go
+++ b/ed25519.go
@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Implements an elliptic.Curve interface over the ed25519 curve.
 package ed25519
 
 import (
@@ -34,6 +33,7 @@ func initEd25519Params() {
 	ed25519Params.BitSize = 256
 }
 
+// Ed25519 returns a Curve that implements Ed25519.
 func Ed25519() elliptic.Curve {
 	once.Do(initEd25519Params)
 	return ed25519