LONDON—Once thought to be the most definitive reference of its kind, Guinness World Records was forced to formally recognize The Ultimate Book of World Records as the world's largest collection of exceptional human achievements and natural phenomena, its publishers announced Tuesday.

"One of our guys went to the bookstore to verify it, and yes, The Ultimate Book lists 57 more world records than Guinness, though the arrangement of the topics is very confusing," a Guinness spokesman said. "Many of the records are pretty trivial and were clearly put in to outdo us, like 'Largest Cookie Wrapped in Cellophane' and 'Widest Lint Brush.'"

Guinness subsequently announced that it would introduce a "Most Prestigious Record Book" category in its 2008 edition.