Dungeon Crawl Classics RPG: The Chained Coffin Hardcover - Rules of Play says:

A hardcover book that compiles all material from the original DCC #83: The Chained Coffin boxed set, including all the stretch goal booklets, as well as much, much more:

• All content from DCC #83.1: Tales of the Shudder Mountains and DCC #83.2: Death Among the Pines
• The Shudder Mountain material published in several Gen Con Program Guides
• Moon Eyes and Fire-Flies, a new adventure set in the Shudder Mountains
• Buzzard Hollow, a new Shudder Mountains mini-setting
• Ma Bigginty’s Book of Backwoods Wisdom, a collection of inspiring material that will bring The Shudder Mountains to life in your game