Hard-core pornography is banned in Texas prisons. So are hate writings or magazines that teach how to build weapons. Also off-limits: The Texas Almanac.

The annual book of lists, statistics and boiled-down information isn't permitted behind bars because its maps are so detailed that prison officials fear they could help escapees."A map would be of great assistance if you were planning to go over the wall," said Larry Fitzgerald, spokesman for the Texas Department of Criminal Justice.

"Once they're outside the walls, they go, `Ooh, I'm out here. What do I do now?' A lot of times they won't have any idea really where they are, what road leads to where," Fitzgerald said.

Would-be escapees would be well-served with the almanac, officials said. Take its map for Polk County, the densely forested East Texas home of the Terrell prison unit. The map is so thorough it includes the tiny towns of Pluck and Ace, Piney and Menard creeks, an Indian reservation and several railroad lines.

The publisher of the almanac, The Dallas Morning News, isn't upset about the ban. The newspaper sees it as a marketing opportunity.

The Morning News recently ran an advertisement for the almanac that bragged: "The powers-that-be feared that inmates might use the detailed county maps to plot escape routes. We're not making this up. If the maps are so good prisoners aren't allowed to read them - imagine what they can do for you."

Fitzgerald said the almanac ($12.95 in paperback, $19.95 in hardcover) has been banned for years - at least the five he's been with the prison system.

The American Civil Liberties Union doesn't think the ban treads unfairly on inmates' rights. Says Jay Jacobson of the ACLU of Tex-as: "I think one might be able to express a legitimate security concern with a detailed map that shows nooks and crannies, every hill and dale."

But defense attorney Tom Mills of Dallas complains that the restriction is just another example of how prisons focus on punishment rather than education.