Do not buy the "updated and revised version" — buy the cheaper version from 1994 (if you want this book). I was shocked to find that aside from the 8-page introduction, next to nothing has been changed from the 1994 version.
Despite calling the disorder ADHD in the intro, he calls it ADD throughout the rest of the book. Despite saying that ADHD affects men and women in equal numbers in the intro, soon after in the book he says that it affects men three times more than women. The research he describes is largely from the early nineties or before, despite the explosion of new ADHD research findings in the past 22 years (although there is updated medication information).
This makes me angry because the author's grab for money in releasing an "updated" version of a book about a disorder that is hardly updated at all is unacceptable and negligent. Clinicians and patients will read this inaccurate/unupdated information and not deliver or receive the best treatment they could potentially have. Dr. Hallowell stresses in his book how dramatically the disorder can negatively affect one's life and how important treatment is — yet he presents vastly outdated information and pretends it's new, doing a great disservice to ADHD sufferers like myself who want to heal.