The Unabomber wants the world to know he's been misunderstood. He says he's not a mad bomber. It's not the "bomber" label that he's addressing. It's the "mad" part. "I'm very different from the kind of person that the media have portrayed with the help of my brother and my mother," Theodore J. Kaczynski writes in the first sentence of "Truth vs. Lies," a 548-page argument that a small publisher says it is issuing this spring. Beau Friedlander, the publisher of Context Books, said the book is "not an ideological tract. It is wholly concerned with addressing the stories that were told about him during his trial. It doesn't touch upon the crimes at all, or the motivation. The one time the word Unabomber' is in the text, it's in the third person." The publisher, based in New York, is issuing its first list this spring. Context is very small -- "Today, we have six employees," said Friedlander. "It goes up and down, depending on my needs" -- and is still in negotiation with a distributor. Kaczynski, whose 16 bomb attacks killed three people and wounded 29 more, was caught after his anonymous manifesto, printed in The Washington Post, was read by his brother. His lawyers were planning to plead insanity, but Kaczynski refused. He pleaded guilty, and is now serving a life sentence. The book is an attempt to prove his sanity, the publisher said. This is vitally important to Kaczynski; if he's considered crazy the message in his manifesto will be dismissed. "I don't think you'll find the same tone" as the manifesto, which was considered pedantic and ill-argued and which hardly anyone read to the end, said Friedlander. "There's some points where this book is very disarming, even funny." He acknowledged that the Unabomber's victims would be unlikely to see any humor. Any money that Kaczynski makes from the book will go to the victims. Friedlander wouldn't give printing figures, but said any royalties were likely to be small. If "Truth vs. Lies" appears as scheduled, it will actually be Kaczynski's second book. After his manifesto was printed in this newspaper, a small press issued it in book form. That volume is now out of print. Context is also publishing Vermont law professor Michael Mello's book on Kaczynski, which argues that he didn't get his day in court. Kaczynski is reportedly seeking a new trial. Friedlander contacted Kaczynski after hearing last year that he had been rebuffed by such big publishers as Simon & Schuster. S&S publisher David Rosenthal said yesterday they had never even bothered to look at a manuscript. "As a general rule," he said, "we try to stay away from homicidal felons." CAPTION: Ted Kaczynski says he wants to set the record straight. ec