As a keen gamer, I plan to show this book to everyone who tells me I'm wasting time! The book explores a premise called the Sleeper Curve, a term invented by Johnson and used liberally throughout the book, explaining that those forms of mass culture that are most slated for being mindless and simplistic are in fact challenging our brains in ever newer and more complex ways. By examining the changes in television, film and games over the last few decades, and citing results of IQ studies and other publications, Johnson certainly makes a persuasive argument for the complexification of American culture.
However, a major flaw with this book as far as I see it is its concentration on America and American media. Whether older British television is indeed as simple compared to today's shows as Johnson claims American TV is, I cannot say; however, I suspect that at least some of our older television still challenges today's audiences. Equally, results of spurious IQ studies (with Johnson himself mentioning that IQ is not necessarily a good measure of intelligence) are entirely divorced from our culture. Having lived in America, I did understand most of the references to television shows, but there were still some which passed me by, unfortunately.
In terms of style the book is fairly heavy-going (at least initially) since it takes a more academic than casual tone. Certainly the term 'Sleeper Curve' is accurate as I fell asleep reading it a few times, and I felt more like I was ploughing through reams of justification than following a series of eloquent arguments. However, Johnson makes his point logically, and well, and I am inclined to agree with his line of reasoning; it is also a good thing for mass media that finally a well-supported argument can stand up to the old-wives' myths levelled at it by its detractors, and the general folk belief that "TV is bad for you" which, I realise, I have never seen actually argued out anywhere.
Overall, this is an interesting and fairly challenging book but a little too America-centric; I feel it wouldn't have been terribly difficult to look outside the USA for examples! If one can look past that, however, it's definitely worth at least one read, though it might not stand up to repeated reading, since my reaction on finishing the book was to want to talk to the author to challenge some of his points -- something the old-fashioned one-way un-interactive medium of books doesn't allow