McGonigal offers a compelling hook -- that games can change us and the world for the better -- and backs it up with psych research and tons of examples. The parts I found most compelling were the tie-ins with positive psychology ("happiness research"), neurochemistry, and productivity. I love the chapter where she explains how gameplay is the opposite of depression and where she describes her own story that inspired SuperBetter (which I read while sick with the flu).

This would be a five-star review except for a few minor things:

1) The writing is only okay. It got a bit wordy and repetitive.

2) The book started losing me around the second half where she was mostly describing her own game designs. I think this is a matter of personal taste, but the descriptions of many of the "reality games" (rather than video games) which are really just a thin veneer for some greater purpose, and where quests are some nebulous, difficult real-world task, whose scoring is entirely subjective -- such as recording a video of yourself dancing -- didn't compel me. Everything she said about the importance of tight feedback loops and fun failure seemed to get lost here -- it felt like bad game design. But apparently the games managed to engage people, so hey, more power to it -- but I didn't personally feel inspired reading about those games.