I think I'd give this book a 3.5, but I nudged it up to 4 stars because it did give me some insights and philosophical reasons to stop procrastinating that were surprisingly helpful.
I came to this book after listening to the author, Ferrari (who seems to be the father of procrastination research), on the "Ologies" podcast (10/10 recommend). I like the way this book provides lots of references to the scientific literature, studies that attempt to learn more about procrastinators and why they do the things they do. I don't think the description of the book as a "guide" on how to get things done is really accurate, but ultimately (as a procrastinator) it did make me WANT to change, which is really the crux of the advice provided in the book.
The book's chapters are designed to be able to stand on their own, I guess so you don't necessarily have to read the entire book if you are short on time. I think this results in the book being a bit repetitive. To me, many of the chapters read like a freshman research paper (sorry), attempting to cram a lot of information into 10-20 pages. I can imagine each chapter being written and edited by itself (in manageable chunks, as suggested), but by the time they got the the later chapters they forgot what they had already talked about lol. I think the whole book is worth reading, but you may find that by the time you get to the last couple chapters, you're not getting much new information. Maybe just start with Chapter 1-2 and see what you think.
There are also some places where the book seems to contradict itself. For example, they reference the phrase "carpe diem" as a philosophy opposing procrastination, but then in the next chapter say that procrastination may have developed because cave people had a "carpe diem" attitude to having food / pleasurable things right away (which is no longer adaptive). In a later chapter, Ferrari uses Dickens' "A Christmas Carol" as an example of procrastination because he wrote it in the 6 weeks before the holiday season. He at first says that because Dickens wrote it at the last minute, it wasn't good enough to be published, but then concludes by praising Dickens for "taking action" and writing the book even if it wasn't perfect. I understand what he's getting at but it just seemed a little all over the place / could have been written better.
During my reading, I often felt that some of the word choices could have been improved. For example, I think that saying a researcher "claimed" something implies that they were incorrect - It feels like they just randomly picked a word out of the thesaurus instead of using a more appropriate word (hypothesized). There are several place in the book that make broad generalizations: "Procrastinators think... Procrastinators are..." that could have been helped (made less offensive) by some percentages or other qualifying words (most, many, etc). Since the author attests to being "not a procrastinator," the book can feel somewhat judgmental at times (although I believe the intention is not to judge, but to be helpful), and some of the conclusions reached in the studies seem a bit far fetched (correlation does not equal causation).
Anyway, I think it's worth a read, but I'm not surprised it doesn't have a five-star rating.