"The majority of people who support the store are people who don't have a lot of money," O'Leary says.

It's a struggle," says store volunteer Jane Sullivan. She adds that during some months, they do make the $1,800 needed to cover the rent.

"[But] we can't rely on sales," she says.

"We have to do benefits, programs, things of that nature."

Sullivan says some supporters don't even agree with the store's ideology, but donate to the store because they appreciate it as an alternative to mainstream bookstores.

The store is the only one of its kind in Cambridge and according to O'Leary, it has moved to five different locations in the course of its 20-year history in the city.

O'Leary says the store was located near MIT, on River Street, and then in the Garage building on JFK Street. O'Leary says the store left its last location to seek refuge from high rents.

The store, although politically affiliated with the Revolutionary Communist, Party, is financially independent, just like other affiliates in California, Florida, Georgia, Hawaii, Illinois, Michigan, New York, Ohio, Oregon, Pennsylvania, Texas and Washington State. O'Leary estimates that on a "good Saturday" the Harvard Square location attracts 40 to 50 people.

Sullivan points to the Square's history to explain the store's attraction. "People come here because it has a history of radical thought," she says.

Bryant says the store's location in Harvard Square is key to the movement's presence in political and academic debate.

"There's a more political discourse in these intellectual areas that we just want to be a part of," Bryant says.

Revolution Books' customers buy items ranging from a mouse pad labeled "Mao's Pad" to Toni Morrison's Song of Solomon. Books in Spanish, French, Farsi, Chinese, Arabic and other languages are available.

According to O'Leary, top sellers include Phony Communism is Dead... Long Live Real Communism, by Bob Avakian, chair of the central committee of the Revolutionary Communist Party of the U.S.

Other favorite buys include Quotations from Chairman Mao Tse-tung and Howard Zinn's A People's History of the United States.

Revolution magazines with the slogan "Mao More Than Ever" line a top shelf. Another shelf is dedicated to the "Great Proletarian Cultural Revolution".