diff --git a/buildah.go b/buildah.go
index 87208a12f..13703825a 100644
--- a/buildah.go
+++ b/buildah.go
@@ -9,55 +9,124 @@ import (
 )
 
 const (
+	// Package is the name of this package, used in help output and to
+	// identify working containers.
 	Package       = "buildah"
-	ContainerType = Package + " 0.0.0"
+	containerType = Package + " 0.0.0"
 )
 
+// Builder objects are used to represent containers which are being used to
+// build images.  They also carry potential updates which will be applied to
+// the image's configuration when the container's contents are used to build an
+// image.
 type Builder struct {
 	store storage.Store
 
-	Type      string
-	FromImage string
-	Config    []byte
-	Manifest  []byte
+	// Type is used to help identify a build container's metadata.  It
+	// should not be modified.
+	Type string `json:"type"`
+	// FromImage is the name of the source image which was used to create
+	// the container, if one was used.  It should not be modified.
+	FromImage string `json:"image,omitempty"`
+	// Config is the source image's configuration.  It should not be
+	// modified.
+	Config []byte `json:"config,omitempty"`
+	// Manifest is the source image's manifest.  It should not be modified.
+	Manifest []byte `json:"manifest,omitempty"`
 
-	Container   string
-	ContainerID string
-	MountPoint  string
-	Mounts      []string
-	Links       []string
-	Annotations map[string]string
+	// Container is the name of the build container.  It should not be modified.
+	Container string `json:"container-name,omitempty"`
+	// ContainerID is the ID of the build container.  It should not be modified.
+	ContainerID string `json:"container-id,omitempty"`
+	// MountPoint is the last location where the container's root
+	// filesystem was mounted.  It should not be modified.
+	MountPoint string `json:"mountpoint,omitempty"`
+	// Mounts is a list of places where the container's root filesystem has
+	// been mounted.  It should not be modified.
+	Mounts []string `json:"mounts,omitempty"`
+	// Links is a list of symbolic links to the currently-mounted container
+	// root filesystem.  They will be removed when the container is
+	// unmounted.  It should not be modified.
+	Links []string `json:"links,omitempty"`
 
-	CreatedBy    string
-	OS           string
-	Architecture string
-	Maintainer   string
-	User         string
-	Workdir      string
-	Env          []string
-	Cmd          []string
-	Entrypoint   []string
-	Expose       map[string]interface{}
-	Labels       map[string]string
-	Volumes      []string
-	Arg          map[string]string
+	// Annotations is a set of key-value pairs which is stored in the
+	// image's manifest.
+	Annotations map[string]string `json:"annotations,omitempty"`
+
+	// CreatedBy is a description of how this container was built.
+	CreatedBy string `json:"created-by,omitempty"`
+	// OS is the operating system for which binaries in the image are
+	// built.  The default is the current OS.
+	OS string `json:"os,omitempty"`
+	// Architecture is the type of processor for which binaries in the
+	// image are built.  The default is the current architecture.
+	Architecture string `json:"arch,omitempty"`
+	// Maintainer is the point of contact for this container.
+	Maintainer string `json:"maintainer,omitempty"`
+	// User is the user as whom commands are run in the container.
+	User string `json:"user,omitempty"`
+	// Workdir is the default working directory for commands started in the
+	// container.
+	Workdir string `json:"workingdir,omitempty"`
+	// Env is a list of environment variables to set for the container, in
+	// the form NAME=VALUE.
+	Env []string `json:"env,omitempty"`
+	// Cmd sets a default command to run in containers based on the image.
+	Cmd []string `json:"cmd,omitempty"`
+	// Entrypoint is an entry point for containers based on the image.
+	Entrypoint []string `json:"entrypoint,omitempty"`
+	// Expose is a map keyed by specifications of ports to expose when a
+	// container based on the image is run.
+	Expose map[string]interface{} `json:"expose,omitempty"`
+	// Labels is a set of key-value pairs which is stored in the
+	// image's configuration.
+	Labels map[string]string `json:"labels,omitempty"`
+	// Volumes is a list of data volumes which will be created in
+	// containers based on the image.
+	Volumes []string `json:"volumes,omitempty"`
+	// Arg is a set of build-time variables.
+	Arg map[string]string `json:"arg,omitempty"`
 }
 
+// BuilderOptions are used to initialize a Builder.
 type BuilderOptions struct {
-	FromImage           string
-	Container           string
-	PullIfMissing       bool
-	PullAlways          bool
-	Mount               bool
-	Link                string
-	Registry            string
+	// FromImage is the name of the image which should be used as the
+	// starting point for the container.  It can be set to an empty value
+	// or "scratch" to indicate that the container should not be based on
+	// an image.
+	FromImage string
+	// Container is a desired name for the build container.
+	Container string
+	// PullIfMissing signals to NewBuilder() that it should pull the image
+	// if it is not present in the local Store.
+	PullIfMissing bool
+	// PullAlways signals to NewBuilder() that it should pull the source
+	// image before creating the container.
+	PullAlways bool
+	// Registry is a value which is prepended to the image's name, if it
+	// needs to be pulled and the image name alone can not be resolved to a
+	// reference to a source image.
+	Registry string
+	// Mount signals to NewBuilder() that the container should be mounted
+	// immediately.
+	Mount bool
+	// Link specifies a location for a symbolic link which should be
+	// created if the container is mounted immediately.
+	Link string
+	// SignaturePolicyPath specifies an override location for the signature
+	// policy which should be used for verifying the new image as it is
+	// being written.  Except in specific circumstances, no value should be
+	// specified, indicating that the shared, system-wide default policy
+	// should be used.
 	SignaturePolicyPath string
 }
 
+// NewBuilder creates a new build container.
 func NewBuilder(store storage.Store, options BuilderOptions) (*Builder, error) {
 	return newBuilder(store, options)
 }
 
+// OpenBuilder loads information about a build container given its name or ID.
 func OpenBuilder(store storage.Store, container string) (*Builder, error) {
 	c, err := store.GetContainer(container)
 	if err != nil {
@@ -72,13 +141,16 @@ func OpenBuilder(store storage.Store, container string) (*Builder, error) {
 	if err != nil {
 		return nil, err
 	}
-	if b.Type != ContainerType {
+	if b.Type != containerType {
 		return nil, fmt.Errorf("container is not a %s container", Package)
 	}
 	b.store = store
 	return b, nil
 }
 
+// OpenBuilderByPath loads information about a build container given either a
+// path to the container's root filesystem or a the path of a symbolic link
+// which points to it.
 func OpenBuilderByPath(store storage.Store, path string) (*Builder, error) {
 	containers, err := store.Containers()
 	if err != nil {
@@ -111,7 +183,7 @@ func OpenBuilderByPath(store storage.Store, path string) (*Builder, error) {
 		}
 		b := &Builder{}
 		err = json.Unmarshal([]byte(buildstate), &b)
-		if err == nil && b.Type == ContainerType && builderMatchesPath(b, abs) {
+		if err == nil && b.Type == containerType && builderMatchesPath(b, abs) {
 			b.store = store
 			return b, nil
 		}
@@ -119,6 +191,9 @@ func OpenBuilderByPath(store storage.Store, path string) (*Builder, error) {
 	return nil, storage.ErrContainerUnknown
 }
 
+// Save saves the builder's current state to the build container's metadata.
+// This should not need to be called directly, as other methods of the Builder
+// object take care of saving their state.
 func (b *Builder) Save() error {
 	buildstate, err := json.Marshal(b)
 	if err != nil {
diff --git a/cmd/buildah/config.go b/cmd/buildah/config.go
index a6492d751..8a5a11df8 100644
--- a/cmd/buildah/config.go
+++ b/cmd/buildah/config.go
@@ -11,6 +11,8 @@ import (
 )
 
 const (
+	// DefaultCreatedBy is the default description of how an image layer
+	// was created that we use when adding to an image's history.
 	DefaultCreatedBy = "manual edits"
 )
 
diff --git a/cmd/buildah/from.go b/cmd/buildah/from.go
index e2efb4768..07bdc9454 100644
--- a/cmd/buildah/from.go
+++ b/cmd/buildah/from.go
@@ -8,6 +8,9 @@ import (
 )
 
 const (
+	// DefaultRegistry is a prefix that we apply to an image name if we
+	// can't find one in the local Store, in order to generate a source
+	// reference for the image that we can then copy to the local Store.
 	DefaultRegistry = "docker://"
 )
 
diff --git a/commit.go b/commit.go
index 2ede35492..f90dbf41c 100644
--- a/commit.go
+++ b/commit.go
@@ -7,11 +7,22 @@ import (
 	"github.com/containers/storage/pkg/archive"
 )
 
+// CommitOptions can be used to alter how an image is committed.
 type CommitOptions struct {
-	Compression         archive.Compression
+	// Compression specifies the type of compression which is applied to
+	// layer blobs.  The default is to not use compression, but
+	// archive.Gzip is recommended.
+	Compression archive.Compression
+	// SignaturePolicyPath specifies an override location for the signature
+	// policy which should be used for verifying the new image as it is
+	// being written.  Except in specific circumstances, no value should be
+	// specified, indicating that the shared, system-wide default policy
+	// should be used.
 	SignaturePolicyPath string
 }
 
+// Commit writes the contents of the container, along with its updated
+// configuration, to a new image in the specified location.
 func (b *Builder) Commit(dest types.ImageReference, options CommitOptions) error {
 	policy, err := signature.DefaultPolicy(getSystemContext(options.SignaturePolicyPath))
 	if err != nil {
diff --git a/config.go b/config.go
index 066387785..589b75e66 100644
--- a/config.go
+++ b/config.go
@@ -121,7 +121,7 @@ func (b *Builder) updatedConfig() []byte {
 		if image.Config.ExposedPorts == nil {
 			image.Config.ExposedPorts = make(map[string]struct{})
 		}
-		for k, _ := range b.Expose {
+		for k := range b.Expose {
 			image.Config.ExposedPorts[k] = struct{}{}
 		}
 	}
diff --git a/delete.go b/delete.go
index bf60ccf42..125087489 100644
--- a/delete.go
+++ b/delete.go
@@ -5,6 +5,8 @@ import (
 	"os"
 )
 
+// Delete removes the working container.  The Builder object should not be used
+// after this method is called.
 func (b *Builder) Delete() error {
 	for _, link := range b.Links {
 		if err := os.Remove(link); err != nil {
diff --git a/link.go b/link.go
index f2ce17d2a..7c38e3e76 100644
--- a/link.go
+++ b/link.go
@@ -6,6 +6,9 @@ import (
 	"path/filepath"
 )
 
+// Link creates a symbolic link in a specified location which points to the
+// root filesystem of a working container.  The container should be mounted
+// using the Mount() method before calling this method.
 func (b *Builder) Link(location string) error {
 	if b.MountPoint == "" {
 		return fmt.Errorf("build container is not mounted")
diff --git a/mount.go b/mount.go
index 1f073d473..f79abd324 100644
--- a/mount.go
+++ b/mount.go
@@ -1,5 +1,7 @@
 package buildah
 
+// Mount mounts a container's root filesystem in a location which can be
+// accessed from the host, and returns the location.
 func (b *Builder) Mount(label string) (string, error) {
 	mountpoint, err := b.store.Mount(b.ContainerID, label)
 	if err != nil {
diff --git a/new.go b/new.go
index 9b8287604..800d56ddc 100644
--- a/new.go
+++ b/new.go
@@ -9,6 +9,8 @@ import (
 )
 
 const (
+	// BaseImageFakeName is the "name" of a source image which we interpret
+	// as "no image".
 	BaseImageFakeName = "scratch"
 )
 
@@ -18,6 +20,9 @@ func newBuilder(store storage.Store, options BuilderOptions) (*Builder, error) {
 	config := []byte{}
 
 	name := "working-container"
+	if options.FromImage == BaseImageFakeName {
+		options.FromImage = ""
+	}
 	image := options.FromImage
 	if options.Container != "" {
 		name = options.Container
@@ -42,7 +47,7 @@ func newBuilder(store storage.Store, options BuilderOptions) (*Builder, error) {
 
 	systemContext := getSystemContext(options.SignaturePolicyPath)
 
-	if options.FromImage != "" && options.FromImage != BaseImageFakeName {
+	if image != "" {
 		if options.PullAlways {
 			err := pullImage(store, options, systemContext)
 			if err != nil {
@@ -103,8 +108,8 @@ func newBuilder(store storage.Store, options BuilderOptions) (*Builder, error) {
 
 	builder := &Builder{
 		store:       store,
-		Type:        ContainerType,
-		FromImage:   options.FromImage,
+		Type:        containerType,
+		FromImage:   image,
 		Config:      config,
 		Manifest:    manifest,
 		Container:   name,
diff --git a/unmount.go b/unmount.go
index 2246bf2eb..62dbe193c 100644
--- a/unmount.go
+++ b/unmount.go
@@ -6,6 +6,8 @@ import (
 	"github.com/Sirupsen/logrus"
 )
 
+// Unmount unmounts a build container, removing any links which have been made
+// to its root.
 func (b *Builder) Unmount() error {
 	err := b.store.Unmount(b.ContainerID)
 	if err == nil {