Singer, songwriter and guitarist John Prine underwent surgeries in 1996 and 2013 that affected his throat and voice. Now, he says, he likes his voice better: “It dropped down lower and feels friendlier.” His new album, ‘The Tree of Forgiveness,’ is his first in 13 years. Also, film critic Justin Chang reviews the new Elvis documentary ‘The King.’ Stephen McCauley’s latest book, ‘My Ex-Life,’ is a comedy about a couple whose marriage ended years ago when the husband came out as gay, but then they become friends. “All relationships evolve — even for people who stay together,” he says.