By Karen Valby
Updated May 11, 2012 at 04:00 AM EDT

Buzz Bissinger, the Pulitzer Prize-winning author of Friday Night Lights, is the father of twin sons, only one of whom suffered brain damage that forever sealed crucial parts of him off from the world. (Zach can understand, for instance, that 9/11 is an important anniversary, but he still called Bissinger to wish him a ”happy 9/11!”) At 24, Zach, who bags groceries and will likely bag groceries his whole life, is kind, generous, and accepting of his own 8-year-old comprehension skills.

But Zach is a mystery to his father. So, Bissinger invites him on a road trip that will take them to every place they have ever lived together. Father’s Day is his gorgeous and brutally honest account of their adventure — an erratic father too eager to connect, a genial, detached son with a savant-like skill for map reading. At a Six Flags outside St. Louis, Zach persuades his dad to go on a 153-foot heart-stopper of a bungee ride called the Dragon’s Wing. The four-page description of their death-defying drop, in which father and son cling in terror and joy as they fall from the sky, is one of the most beautiful metaphors for parenthood I have ever read.

Occasionally Bissinger interrupts the flow with clinical tangents, like the horrifying treatments once inflicted on premature babies and a history of savantism. I’m guessing these bits offered Bissinger a chance to reset his emotional barometer, but I always found myself anxious to get back to the story. Father’s Day seems like a wrongheaded title, chosen by a marketing department for its muscular sentimentality. As much as this is a book for parents, who know well the crushing vulnerabilities of the job, it is also a story for grown children who understand what it means to love an imperfect parent. Would that we were all as forgiving as Zach. A