Rock Jaw: Master of the Eastern Border

Rock Jaw:
Master of the Eastern Border
First US edition cover
AuthorJeff Smith
IllustratorJeff Smith
Cover artistJeff Smith
Elizabeth Lewis
LanguageEnglish
SeriesBone
GenreFantasy, comedy
PublisherCartoon Books
Publication date
September 1, 1998
Publication placeUnited States
Media typeHardback and paperback
Pages128
ISBN1-888963-02-6 (hardback)
ISBN 1-888963-03-4 (paperback)
OCLC41882709
Preceded byThe Dragonslayer 
Followed byOld Man's Cave 

Rock Jaw: Master of the Eastern Border is the fifth book in the Bone series. It collects issues 28-32 of Jeff Smith's self-published Bone comic book series. The book was published by Cartoon Books in its original black-and-white form in 1998. Paperback and hardback coloured editions were published in February 2007 by Scholastic.

This book focuses on the journey of Fone Bone and Smiley Bone. They travel to the mountains to return a baby Rat Creature back to his own kind. On the way, they are interrupted by Roque Ja (whose name the Bones mispronounce as "Rock Jaw"), a giant and enigmatic mountain lion. They spend the rest of their journey teamed up with a band of orphans to escape Rock Jaw. On this adventure Fone Bone and Smiley Bone also have to escape Kingdok. Notably, it is the only book in the series to not feature the characters of Phoney Bone, Thorn Harvestar, Gran’ma Ben, and Lucius Down.