A self-proclaimed skinhead is suing his Denver middle school and principal on grounds they infringed on his rights by banning a book, clothes and ideas not sanctioned by the school district.

Attorneys for the American Civil Liberties Union filed the suit Monday in Denver District Court on behalf of Demian Marienthal, 13, and his mother, Judith Marienthal. The suit names Grant Middle School and its principal, Patricia Ana DeLeon.Demian's attorney, Charles Mortimer Jr., said the boy was reading "The Anarchist's Cookbook" last November in detention when a monitor reported him to DeLeon.

The principal confiscated the book, which "tells you how to be an anarchist," and has refused to return it, he said. The book also offers instruction on making bombs.

Mortimer said that last month Demian - "who's learning to be a skinhead" - was summoned to the principal's office and "lectured as to why he shouldn't be a skinhead."

Judith Marienthal subsequently received a letter from the principal disapproving of Demian's "association, philosophically with a non-approved group called the skinheads . . . (and) any form of clothing which identifies them as being a member."

Mortimer said Demian has been permitted to wear his army flight jacket and boots, but not his metal rings and Confederate flag emblem.