The Tyranny of E-mail: The Four-Thousand-Year Journey to Your Inbox by John Freeman (Scribner, 2009).
I have to say I wasn't overly impressed. While I agree with much of what the author writes, I found the book simplistic and many of the points made are obvious (at least to someone who used email before most people had ever heard of it). This book could have been written (much shorter) as an article in a magazine.
After initial observations on the explosive growth of email, Freeman launches into a rather superficial history of communication from clay tablets to early mail to the growth of the modern postal system. He discusses the lost art of letter writing and the picture postcard craze of the 19th and 20th centuries. Telegraphs and typewriters lead into an introduction of the origin and growth of the Internet and email.
Quite honestly, I've read deeper, less superficial, discussions of these topics on Wikipedia.
The book wraps up with lots of anecdotes (and no references to actual studies) of how some people are apparently addicted to email and how computers and electronic gadgets take up more and more of our lives. As someone who's a heavy user of computers, maybe I have a problem too, but I would remind people that I'm sitting here writing this in my living room on a weeknight at 8:30 pm with the television turned off. I think many more people are addicted to television than computers or email.
While I do know people who are addicted to their "Crackberries" checking work email on Friday evenings during happy hour in the bar, I also know plenty of other people who set limits on when and where they'll check their email (especially important as a professor - students will sometimes email you at 2 am on a Saturday night and get annoyed you don't answer until 9 am Monday morning!).
Bottom line, summarizing the entire book, is we all need to slow down and not let email and the Internet take over our lives. There, I just saved you a few hours of reading - go out and smell the roses with that saved time (or check your inbox - whatever).