User blog comment:The Milkman/Skyrim Game Guide Revised and Expanded/@comment-5499262-20120917140326/@comment-3428817-20120924034059

They did that for Fallout 3. There were two companion guides, each covered two DLC's. But the the fifth DLC, Mothership Zeta, never made it into either of the companion guides until the GOTY edition guide was published, then the main game, plus all five DLCs were brought together in one guide.