The book: Getting to Plan B: Breaking Through to a Better Business Model, by John Mullins and Randy Komisar; Harvard Business Press; September 2009.

The big idea: Entrepreneurs rarely nail their business models the first time around. Some of the most successful companies are unrecognizable from their young, naive selves. But after rejiggering, their founders came out aces. You can, too.

The backstory: John Mullins is a professor at London Business School. Randy Komisar is a partner at Kleiner Perkins. But this isn't an apologia for the investor class. "The day you take a dollar or pound or rupee from most capital investors is the day you have agreed to sell your business," they warn.

B is for ballsy: Connoisseurs of entrepreneurial chutzpah will relish tales of Ryanair ordering planes without seatback pockets to reduce turnaround times and Patagonia's Yvon Chouinard recycling underwear.

If you read nothing else: The first two chapters describe a tidy process for business-model tire kicking: Identify a company to emulate ("I want to be the Starbucks of body piercing!") and one to avoid emulating. Test and tweak beliefs about the model. ("Seniors represent the next big body-piercing market.")

Rigor rating: 7 (1=Who Moved My Cheese?; 10=Good to Great). Mullins's research into business models and Komisar's experience with his portfolio companies are buttressed by extensive use of secondary sources.