John Green writes novels for young adults, but you don't have to be young to enjoy them. I'm forty-three, and he's one of my favorite contemporary authors. I became a fan of Green not by reading his books but by watching videos on his amazing YouTube channels CrashCourse, Mental Floss, and Vlogbrothers. I thought I was too sophisticated and mature to read a young-adult novel, but I love Green so much I gave him a shot.
