On a recent morning at Rockefeller Center, NBC employees strolled through the crowd with copies of Upward Bound, the latest book-club pick from the Today show co-host Jenna Bush Hager. “It’s deeply heartfelt and moving,” Hager said, after holding up the debut novel from the 28-year-old Woody Brown, “and the reason it’s so authentic is that the author understands autism firsthand.” That understanding is indeed profound.