Nearly all the nine stories in Junot Díaz’s National Book Award-nominated collection center on Yunior, Díaz’s literary alter ego, a clumsy cheater and desperate-to-please lover who burns through girlfriends the way runners burn through oxygen. From Miss Lora—a teacher at his high school—to the overly romantic Magda to the artistic Alma, Yunior learns This Is How You Lose Her (Riverhead, $26.95): by two-timing, by lying, by being too Dominican, by not being Dominican enough. Yunior picks up tips on relationships from his libertine older brother, Rafa, who adopted the values of the brothers’ duplicitous, controlling father. Alas, the women in Yunior’s world ultimately prove to need Yunior far less than he needs them. Díaz, a recently named MacArthur genius, deftly braids socio-economic and identity issues into each story’s tiny universe; his stories mirror our own jumbled, complex, and complicated world.