A suburban Atlanta school board that put stickers in its high school science books that said evolution is "a theory, not a fact" abandoned the legal battle Tuesday after four years.

The Cobb County board agreed in federal court never to use a similar sticker or to undermine the teaching of evolution in science classes.

In return, the parents who sued over the stickers agreed to drop all legal action.

"We certainly think that it's a win not just for our clients but for all students in Cobb County and, really, all residents of Georgia," said Beth Littrell of the ACLU of Georgia.

The school board placed the stickers on the cover of biology books in 2002 after a group of parents complained that evolution was being taught to the exclusion of other theories, including the Biblical story of creation.

The stickers read: "This textbook contains material on evolution. Evolution is a theory, not a fact, regarding the origin of living things. This material should be approached with an open mind, studied carefully and critically considered."

A federal judge ordered the stickers removed in 2005, saying they amount to an unconstitutional endorsement of religion. The school board appealed, but a federal appeals court sent the case back, saying it did not have enough information.

"We faced the distraction and expense of starting all over with more legal actions and another trial," said board chairwoman Teresa Plenge. "With this agreement, it is done and we now have a clean slate for the new year."