I started sneaking up on a science fiction writing career back in grade school, when I tried to do a sequel to a Mickey Mouse story involving being shrunken down to subatomic size ala Ray Cummings. In high school, I did articles and sf columns for the local newspaper, but five cents a column inch and a reluctance to talk to strangers didn't bode well for a career in journalism.
I soon discovered fanzines, like Yandro and Fan-Fare and The Chigger Patch of Fandom, which were more fun but paid nothing at all, so I became an electronics tech for a few years. Luckily, that led me into tech writing, which lasted for fifteen years, including five on the Apollo program, where I wrote manuals and programmed instruction texts on the LEM and Command Module guidance systems. The most fun, though, was using an "intuitive" approach to the basics of orbital mechanics when I wrote a series of texts for NASA. It was the sort of thing that, if it were published today, might be called "Space Flight for Dummies," and go on the shelves with all the " . . . for Dummies" computer books. It also got me a couple of trips to NASA sites, including a ride to the top of the Vertical Assembly Building.
The first fiction sale was a Man from U.N.C.L.E novel, a collaboration with Robert Coulson under the name Thomas Stratton (my unused first name and his middle name). It has been the distinction of being the only sale I know of in which the title, the author's names, and the dedication were all rejected but the manuscript was accepted (except for a reference to a dirigible that wasn't house broken, which they edited out). Since then I've plowed through about forty books (including five more collaborations with Coulson) in various categories including science fiction, mysteries, horror, and romance, even nonfiction ones on computers (despite being largely computer illiterate) and doll making. One novel was published in four separate categories in different editions and translations, from straight mystery to horror. I've also done YA SF that grownups can enjoy as well as kids (I hope). One -- Adventures of a Two-Minute Werewolf -- was made into an ABC Weekend Special a few years back. I've also done a few Star Trek novels and one each for Lost in Space and Dinotopia.