diff --git a/backends/doc.go b/backends/doc.go
new file mode 100644
index 0000000..d32bd15
--- /dev/null
+++ b/backends/doc.go
@@ -0,0 +1,3 @@
+// Package backends contains sub-packages that register backends with tomo when
+// linked into a program.
+package backends
diff --git a/backends/x/doc.go b/backends/x/doc.go
new file mode 100644
index 0000000..cf0649d
--- /dev/null
+++ b/backends/x/doc.go
@@ -0,0 +1,2 @@
+// Package x implements an X11 backend.
+package x
diff --git a/dirs/dirs.go b/dirs/dirs.go
index 966bd5b..3e62b18 100644
--- a/dirs/dirs.go
+++ b/dirs/dirs.go
@@ -1,3 +1,4 @@
+// Package dirs provides access to standard system and user directories.
 package dirs
 
 import "os"
diff --git a/flow/flow.go b/flow/flow.go
index e2a0f23..bd794cf 100644
--- a/flow/flow.go
+++ b/flow/flow.go
@@ -1,3 +1,4 @@
+// Package flow allows an asynchronous process to be written sequentially.
 package flow
 
 // Flow represents any multi-stage process that relies on callbacks to advance
diff --git a/input/input.go b/input/input.go
index b523829..2b10528 100644
--- a/input/input.go
+++ b/input/input.go
@@ -1,3 +1,4 @@
+// Package input defines keyboard and mouse code constants.
 package input
 
 import "unicode"
diff --git a/layouts/layout.go b/layouts/layout.go
index d538e5f..1bb9312 100644
--- a/layouts/layout.go
+++ b/layouts/layout.go
@@ -1,3 +1,8 @@
+// Package layouts defines a layout interface which a container element can
+// accept to have its child elements automatically arranged by any layout that
+// satisfies it.
+//
+// Sub-packages of layouts contain several pre-made ones.
 package layouts
 
 import "image"
diff --git a/popups/doc.go b/popups/doc.go
new file mode 100644
index 0000000..1549570
--- /dev/null
+++ b/popups/doc.go
@@ -0,0 +1,3 @@
+// Package popups provides a set of pre-made pop-up windows such as dialog
+// boxes.
+package popups
diff --git a/shatter/shatter.go b/shatter/shatter.go
index 69c4407..806dfda 100644
--- a/shatter/shatter.go
+++ b/shatter/shatter.go
@@ -1,3 +1,4 @@
+// Package shatter provides boolean operations for image.Rectangle.
 package shatter
 
 import "image"
diff --git a/theme/doc.go b/theme/doc.go
new file mode 100644
index 0000000..3dcc0ae
--- /dev/null
+++ b/theme/doc.go
@@ -0,0 +1,2 @@
+// Package theme implements a theming system for tomo.
+package theme