Hulk: Heart Of The Atom, starts with Incredible Hulk #140, featuring Harlan Ellison's story "The Brute That Shouted Love At The Heart of the Atom," and features further stories starring Jarella and the realm of K'ai that appeared through the early 1980s. It is the same content as the 2008 hardcover "Marvel Premiere Classic" edition, but in a softcover format with a new cover.
In addition to Incredible Hulk #140, this book reprints Incredible Hulk #148, 156, 202-203, 205-207, and 246-248, along with What If? #23: "What If... Hulk's Girlfriend Jarella Had Not Died?" (or "What If The Hulk Had Become A Barbarian?" as it is described on the cover. Note, this collection does not include Avengers #88 which featured the first part of the story in Incredible Hulk #140.