When I was 12, I saw Witness for the Prosecution for the first time. Holy crap, I thought, as I watched Marlene Dietrich. She rules. (The joy of viewing such an assured performance at the hateful age of 12—especially when one is cursed with clumsiness and bulkiness—cannot be underestimated.) Dietrich was cool and tough—and she had a voice that compelled me to lean forward and stare, unblinking, at our 13-inch black-and-white Hitachi. In her new book, The Girls: Sappho Goes to Hollywood, Diana McLellan writes about the glamorous women of Hollywood’s golden era—including Dietrich, Greta Garbo, and Tallulah Bankhead—and the women who loved them. McLellan will discuss the results of her five years of research at 4 p.m. at Barnes & Noble, 12089 Rockville Pike, Rockville. Free. (301) 881-0237. (Jennifer Agresta)