The "Boston Legal" star is the co-author of a new book, which tells his life story.

"Star Trek" made WILLIAM SHATNER a star, and "T.J. Hooker" and, most recently, "Boston Legal," which returns in the fall for its final season, proved that he was much more than a one-hit wonder, rather he's a talent to remember.

Now, the actor and Priceline.com pitchman has written all about his adventures in front of and behind the camera in a recently released book and audio book: Up Till Now: The Autobiography, which was co-written by DAVID FISHER.

"I don't think the people close to me, my children, friends and wife, know some of my inner thoughts," Shatner tells ET of his decision to write his memoirs. "It's a form of a legacy. A sort of memoir: Here's what your father/husband was thinking or doing on such and such a date."

Shatner says he made the tome as "truthful, earnest and honest" as possible, but at the same time, he wanted it to be entertaining, so there are laughs. And to make sure that the audio book version got just the right treatment, he read it himself.

"I don't think you're going to find too many people better at reading a book, let alone my own book, than I can," he says.

But the book isn't all laughs. Shatner also deals with the tragic death of his wife, who drowned in a swimming pool at the couple's home.

"One of the charities that I maintain is the NERINE SHATNER Friendly House," he continues. "It's a rehabilitation house for women who are addicted, and it's in memoriam to my wife. It's helped many, many women to overcome their addiction."

Shatner tells ET that he learned a lot from Nerine's death: "How ephemeral life is. How quickly life is over. How fragile we are ... and how precious life is and how much you must cherish it."