HarperCollins. 367 pp. $26.95Jack Forman, the narrator and protagonist of [Michael Crichton]'s new techno-thriller, lost his job at a Silicon Valley outfit called MediaTronics for "gross negligence and misconduct," another way of saying he caught the owner of the privately held company dipping his hand into the till. Jack's been out of work for six months. He's 40 years old and an experienced research analyst, but in the incestuous high-tech community, his experience at MediaTronics has marked him as a troublemaker. He's having a hard time finding work, even though his field, "multi- agent distributed processing," is "hot."

So he stays home as househusband while his wife, Julia, goes to her job at Xymos, a small but up-and-coming company deep into "what the company called 'molecular manufacturing,' but which most people called nanotechnology." It has a fabrication plant out in the Nevada desert to which Julia travels with ever greater frequency and for ever longer periods. When she does come home, she's distant with Jack and their three young children, short-tempered, indeed "everything about her was different." Jack is convinced that she's having an affair, and that the various complaints she issues against him are aimed at building an alienation-of-affection case that would permit her to divorce him and get custody of the children into the bargain.

That company, you will not be surprised to learn, is Xymos. So there goes Jack, out to the desert to find out what's going on in the remote laboratory where his own wife is engaged in mysterious and perhaps terrifying business. To wit, Xymos is into molecular manufacturing, a "phenomenally difficult" and time-consuming process. Xymos, it soon develops, has gotten around the problem by "using a hybrid technology," i.e., it's growing E. coli cells and then, according to Ricky Morse, who's in charge of the program, "we build on them with nanoengineering procedures."