Every hero hears the call to adventure. So, too, then must a critic — perhaps the most passive of all protagonists — discover the stylistic and aesthetic tools needed to tell perfect strangers how to think about a work of art. In Roger Ebert’s new memoir Life Itself, the critical call to adventure occurs after first seeing legendary director Ingmar Bergman’s drama of existential dread, Persona: “I didn’t have a clue how to write about it. I began with a simple description: “At first the screen is black. Then, very slowly, an area of dark grey transforms itself into blinding white. This is light projected onto the screen, the first basic principle of the movies. The light flickers and jumps around, finally resolving itself into a crude cartoon of a fat lady.” And so on. I was discovering a method that would work with impenetrable films: Focus on what you saw and how it affected you. Don’t fake it.” Roger Ebert has never faked it. The passion and clarity with which he writes about movies in his memoir is infectious, reminding us why, as America’s most influential cinematic tastemaker, he is the critic who launched a thousand cinephiles. Ebert’s promotion to film critic of the Chicago Sun-Times at age 25 and his rapid ascent to multi-media cultural mainstay is chronicled in several wonderfully entertaining chapters that form the narrative spine of this book. Along with Bergman, film luminaries Martin Scorsese, Russ Meyer, Robert Altman, Woody Allen, John Wayne, Werner Herzog, Robert Mitchum and Lee Marvin are portrayed with such grin-inducing gusto that it’s a constant temptation to put the book down and just watch their movies. Aside from movies, we quickly discover, Roger Ebert loves a lot of other things too: Full-figured women; 1957...