FORTUNE — What kind of book did Richard Kirshenbaum set out to write? I kept asking myself that question while reading Madboy, a slim volume of anecdotes and observations from Kirshenbuam’s life and 28-year career in the advertising business. The prologue, filled with the names of B-listers such as Nicole Richie, Ed McMahon and Joan Jett, suggests that the reader is about to dive into a juicy memoir — a behind-the-scenes look at the chaos and creativity that goes into making great marketing campaigns.

The book then veers, promisingly (and alas, fleetingly) into “business book” territory: Just a few chapters into his story, Kirshenbaum dives into the founding of Kirshenbaum Bond + Partners, the ad agency he and Jon Bond formed when they were still in their late 20s. His writing comes to life as Kirshenbaum describes his early scramble to win new business and the cheeky publicity stunts the firm employed to win extra attention for its clients.

But rather than making these lively case studies the centerpiece of a book on innovation or unconventional thinking, Kirshenbaum shifts gears once again, and by the middle of the book he’s offering advice on how advertising executives’ spouses should behave at the office. Seriously. It’s odd.

This lack of focus is a shame, because Kirshenbaum has a great story to tell: When he and Bond launched their eponymous firm they were the enfants terribles of the ad business. He and his agency were the first to stencil marketing messages on city streets, for example, and they generated quite a bit of buzz with irreverent campaigns that people are still talking about. (Donna Rice hawking “No Excuses” jeans, Wendy the Snapple Lady, and more.)

But Kirshenbaum doesn’t offer a deep understanding of what goes into developing, pitching, tweaking, and packaging those quirky campaigns. Nor does he shed much light on the big issues facing his industry today. (He and Bond sold the agency, now known as kbs+p, to MDC Partners (MDCA) What does the one-time wunderkind think of the rise of social media as a marketing tool? How are kbs+p’s clients reaching consumers amid the proliferation of media platforms? What’s the tablet-era equivalent of street stenciling? Kirshenbaum may know, but he’s not telling — at least not in this book.

Nor is he dishing much dirt, despite a cast of characters that is most dish-about-able. Actor Bruce Willis is “engaging.” Donny Deutsch is “my big brother in the ad biz.” Joan Collins “is really gorgeous.” Even Paris Hilton, who had a stint as an assistant at kbs+p for an episode of a reality-television show, escapes unscathed. He takes a few anonymous digs, and while Kirshenbaum just may be a genuinely nice guy, the reader can’t help but think he’s holding back some really good material.

To wit, he writes that convincing Snapple’s owners that building an ad campaign around one of its employees, Wendy Kaufman, wasn’t easy: “The fact that Wendy had the crazed Long Island accent, was a real Jewish broad, and had been in drug rehab didn’t help matters, either.” Wait. The Snapple Lady had been in rehab? Kirshenbaum says no more on the matter. Similarly, he declares, “Having seen and been through companies in transition, I can honestly say there is an entire book in how Quaker managed to buy and lose something like $1.4 billion on Snapple.” (The Quaker Oats Co. bought Snapple for $1.7 billion in 1994 and sold it to Triarc in 1997 for $300 million.) But Kirshenbaum, who says he watched the demise up-close, offers no insights other than a vague line or two about corporate destruction of a cult brand.

There’s no question Kirshenbaum has a real joie de vivre, and his writing is unpretentious and enthusiastic — like so many of his marketing efforts. But too often he skims the surface of an idea or anecdote, a formula that may work with ad copy but leaves a book reader wholly unsatisfied.