“I arranged to meet Joan Didion in 1971 after reading Slouching Toward Bethlehem. I found her essays hypnotic, in a voice I’d never heard, expressing ideas I knew were true but couldn’t have articulated. I was reporting for several magazines and asked a colleague who’d met her to introduce us. He gave me her number and when I was in LA, I took a deep breath, dialed it, and her husband, John Gregory Dunne, picked up the phone. I asked for Joan Didion. … Although she’s shy and can be reticent with strangers, we had much in common: we’d grown up in California, gone to Berkeley, joined a sorority and quit, majored in English and studied with Mark Schorer but in different decades—she in the 1950s, I in the 60s. We talked and laughed until the early hours, and in the many dinners and visits that followed, over more…