"Bo Knows Bo." And now, readers can know Bo, too.

"Bo" is Bo Jackson, professional baseball player for the Kansas City Royals, professional football player for the Los Angeles Raiders, and commercial spokesman for brands of sneakers, soft drinks and long-distance telephone service.With the assistance of veteran writer Dick Schaap, Jackson has put together an autobiography. It is natural to expect the life story of such a relatively young person - Jackson is 28 - to be a proportionately short book, Jackson's many achievements notwithstanding. And this slim volume would take up even less space on the shelf had Jackson's reminiscences not been fleshed out with Schaap's observations of the private Bo Jackson - with family, filming a TV commercial, eating in a restaurant and appearing on "Sesame Street."

He was born Vincent Edward Jackson, named for his mother's favorite TV actor, Vince Edwards, who played Dr. Ben Casey. He became known as Bo because, he writes, as a child he was "tough as a wild boar. They called me Bo'-hog, which is a Southern term for a wild boar, and then they shortened it to Bo."

The eighth of 10 children, Bo grew up in Alabama poverty. ("When we got a new outhouse, we thought that was heaven. Kids came to see it.") His childhood was a fatherless one - Bo knew his father, but his father didn't live with the family - and growing up fatherless seems to haunt him still.

Bo relates that as a youngster, he was a bully, extorting money from schoolmates who were smaller and weaker - a description that probably fit most of them. But his mother was not one to spare the rod, and by the time Bo was a junior high school student, he decided to change.

"I finally woke up," he writes, "finally realized that my mom was right, that the way I was going, I was just looking for trouble," heading straight to reform school or worse.

Aside from his several careers, Bo is a devoted husband and father, a muscular man who can stand up to the strongest opponent on the field, but who can easily be put at the mercy of a tiny child.

Jackson is "the best athlete I've ever seen," writes Royals teammate George Brett in an "appreciation" that prefaces the book. And surely, Jackson is also one of the toughest - but not when it comes to needles:

"I hated when they took blood. I'm afraid of needles. They hurt. I got so light-headed once when a nurse just pricked my finger. I had to lie down. I'm serious. It terrifies me."