WASHINGTON -- O.J. Simpson is writing a book to answer the 300,000 pieces of mail he has received since his arrest last June. Probably one piece in particular really energized him: the bill from his legal team.


The book, entitled "I Want to Tell You," is expected to feature the unsurprising declaration that Simpson is innocent. It is due to appear next month, when his trial for murder is set to begin.


Besides coming up with a quick fix for Simpson's lawyers, the book will be another salvo in the public-relations wars between the defendant and the prosecution. Already Sunday there was speculation that the prosecutors would seek out an early copy of the manuscript, and that the trial would be delayed.


Little, Brown, which is issuing the Simpson book, says it is printing 500,000 copies. Presumably that means Simpson will be getting significantly more than $1 million as a result of the project, although he will doubtless have to share a chunk with co-writer Lawrence Schiller. A packager of literary projects, best known for his work with Norman Mailer on "Marilyn" and "The Executioner's Song," Schiller is a former neighbor of Simpson's.


Early reaction to the book ranged from outright condemnations -- "disgusting ... outrageous," Fred Goldman, the father of victim Ron Goldman, told KABC-TV in Los Angeles -- to cautious predictions. "Even if people are a little upset he's writing it, they'll still buy it," said Shirley Smyth, a manager at the Tattered Cover in Denver, one of the country's largest bookstores.


"I Want to Tell You," which is explicitly not being called an autobiography, had been quietly shopped around New York publishing circles for as much as a month. Charles Spicer, a senior editor at St. Martin's Press who specializes in true-crime books, said he turned it down before Christmas.


"My reaction was, first, I was sort of uncomfortable about it, and second, I didn't think there was really a market for it," he said. "What really makes true-crime books take off is when they present readers with a disinterested view. In this case, you know you're not getting a disinterested view."


This is apparently the first time a murder defendant has published a book during his trial. Usually the defendant waits until it's over. If found guilty, he frequently doesn't get a chance at all.


Jean Harris, who shot Herman Tarnower, known as the "Scarsdale Diet" doctor, is one of the very few murderers who was nevertheless judged appealing enough for a full-scale, high-profile book.


When sympathy is lacking, publishers shy away because they think the public will, too. Lionel Dahmer, who was the late cannibal Jeffrey's father, was the latest to demonstrate this. First, his motives were criticized; then his book disappeared.


The book is only the latest money-making venture Simpson has launched from his jail cell to offset mounting legal bills and dwindling personal assets.


Last month a Los Angeles firm began marketing a 21-inch-high, 30-pound bronze sculpture of "The Juice" wearing his trademark No. 32 football jersey and holding a football on his hip. Simpson, whose autograph is inscribed at the base, will receive an unspecified percentage of the sales, according to the marketing firm that designed the statue, with suggestions from Simpson, as he awaited trial.


Also last month, a coin commemorating Simpson's record 1973 rushing season with the Buffalo Bills went on the market with Simpson's approval of the design and marketing strategy.


And last summer Simpson, fulfilling a contract he signed before he was arrested, was reported to have autographed more than 2,800 football trading cards in his jail cell. They were sold to collectors around the country.


Dealers said the value of unsigned Simpson trading cards shot up from a pre-indictment price of $175 to between $400 and $500 in Los Angeles before gradually falling to their earlier level. The signed cards started at $1,000 last August. Dealers have been quoted as saying they expect to reach $1,600 to $2,000 apiece by the start of the trial.