diff --git a/container/doc.go b/container/doc.go
new file mode 100644
index 0000000..76bb6f7
--- /dev/null
+++ b/container/doc.go
@@ -0,0 +1,2 @@
+// Package ucontainer extends container and implements generic container types.
+package ucontainer
diff --git a/image/color/doc.go b/image/color/doc.go
new file mode 100644
index 0000000..bd63bb6
--- /dev/null
+++ b/image/color/doc.go
@@ -0,0 +1,2 @@
+// Package ucolor extends image/color.
+package ucolor
diff --git a/image/path/doc.go b/image/path/doc.go
new file mode 100644
index 0000000..0de5394
--- /dev/null
+++ b/image/path/doc.go
@@ -0,0 +1,2 @@
+// Package upath implements operations on slices of image.Points.
+package upath
diff --git a/io/doc.go b/io/doc.go
new file mode 100644
index 0000000..a0251ee
--- /dev/null
+++ b/io/doc.go
@@ -0,0 +1,2 @@
+// Package uio extends io.
+package uio