This was a re read for me. Back in the day I was an disorganized freak. I could find nothing to save my life. A friend recommended this book so I read it (can you tell I will read almost anything someone recommends?) Any way the book did help to some degree. When I remember to use the principals in the book that is.
In all seriousness though if you are disorganized and you miss deadlines and stuff or you miss very important events (like me) David Allen has some very good recommendations that can help you get a better hold on things.
I still remember when GTD was the latest fad. It is still going strong judging by the amount of GTD stuff on the internet and other book that have been written about it. One book about it is enough for me though.While I like the book and it concepts there is only a certain amount they can say without rehashing the same stuff over and over again. When they make a book that can actually do the organizing for me then I will be more interested. In all fairness though the book does work so read it if you are looking to put some order in chaos.