From a distance, the scene on the lawn of the old Chester County Courthouse in West Chester seemed a Christmas classic.

Ornaments in hand, a red-clad woman stood high on a stepladder, smiling merrily at a 12-foot evergreen. "A little forward," Margaret Downey called down to a young man holding the rungs.

Grasping the tree, she attached a yellow sheet of paper to a branch. Along with dozens of other facsimiles of book covers, A Portable Atheist by Christopher Hitchens fluttered in the December breeze.

Downey, founder of the Freethought Society of Greater Philadelphia, declared it "Good!" and reached for the cover of Gospel Fictions by Randel Helms.

The society's "Godless Holiday Tree" - decorated entirely with book covers about atheism, religious skepticism and secular philosophy - took its provocative place yesterday alongside West Chester's Nativity creche and the Chamber of Commerce's towering artificial Christmas tree. A Hanukkah menorah soon will join the tableau.

"This helps to balance and shows the diversity of the community," Downey said of what her group also calls the "Tree of Knowledge."

Although this was only their second annual installation, Downey and her fellow atheists were a presence on the courthouse lawn as early as 2001. That year, they sued the county to remove its large, bronze Ten Commandments plaque from the face of the stately courthouse.

The society won in federal court, which agreed that the plaque represented an unconstitutional endorsement by government of a religion, but lost when an appeals court ruled that the 1920s-era plaque could stay, in light of its age and "historical significance."

After the fracas, Chester County opened the courthouse lawn to seasonal displays. The creche and a Hanukkah menorah soon followed.

"We'd love to see Kwanza candles and a Buddha statue, too," Downey said.

The "Godless Holiday Tree" will greet - or challenge - passersby with the covers of scores of titles including The Myth of Nazareth by Rene Salam, Why I Am Not a Muslim by Ibn Warraq and Misquoting Jesus by Bart Ehrman. The Bible and the Koran hang there, as well.

"We want people to read these kinds of books so they can make up their minds about religion, not just be spoon-fed by pastors and priests and rabbis," Downey explained.

Directly across High Street, at the Market Street Grill, their atheistic missionizing was greeted with dismay.

"Why do they have do that now?" wondered Laura Walsh, 30, of Glenside, who was sitting at the window table with six family members, planning Christmas dinner.

"It's very stupid," opined Carolyn Gott, of Wilmington, who was wearing a jeweled cross around her neck.

"It's terrible. And the tree is ugly," said Peggy Carroll.

"We should pray for them," said Marian Feeley of Newark, Del., and the others chuckled in agreement.

"We should tell them that!" said Frances Phaneuf of Downingtown.

But the group chose not to.

The freethinkers went about their decorating yesterday afternoon with little interaction from passersby. But they were prepared nonetheless, said Downey. "We decided just to laugh."

Staks Rosch, a society member and host of the Web site, said Christianity's "monopoly" on western thought had spurred him into helping raise the tree.

"I'd like to break up that monopoly so we have a free market of ideas - just to balance things out," he said. "This tree of knowledge is a celebration of good ideas, of science, of history."