*** “MUSICIANS IN TUNE”, By Jenny Boyd, with Holly George-Warren. <i> Fireside Books ($12)</i>

How many psychology Ph.D. candidates get access to 75 top-flight contemporary musicians for their dissertation? Boyd did. It probably didn’t hurt that the ‘60s London fashion model used to be married to Mick Fleetwood and is the ex-sister-in-law of both George Harrison and Eric Clapton. Boyd tapped those three and others for insights into the creative process, from nurturing to drug use to coping with the burden of genius. She avoids both dry academics and gossipy name-dropping while eliciting many illuminating anecdotes, as well as some comments worth a wink or two, including Sinead O’Connor’s confession that “I smoke dope quite a lot. . . . Not when I’m on stage or in the studio . . . but when I’m actually writing.”

Items in this periodic survey of pop-related books, videocassettes and laser discs are rated on a scale of one asterisk (poor) to five (a classic).