Improve Your Poker is a very good book that I believe will stand up well to re-reading. Unlike the many books that attempt to be relatively comprehensive in their coverage, Ciaffone in this book sets as a more attainable goal simply to give the reader thought-provoking material on a wide range of subjects. While I wouldn't want to try to learn poker as a novice from a book like this, I think this format serves the book's stated purpose (to improve your poker) ideally. The individual chapters are short (typically 3-4 pages) but I think tend to provide an appropriate level of detail.
The book is divided into ten sections: General Concepts, Gambling Skills, Reading Opponents, Deception and Bluffing, Hold'em, Omaha, Stud, High-Low Split, Big-Bet Poker, and Tournaments. I really wasn't all that conscious of the transitions between sections as I read the book. For one thing, they're not marked in the text. But also, the section headings are more indicative of general themes than encapsulation of the topics. So, for example, hold'em, omaha, and big-bet poker are topics that span the entire book, and are not restricted to parrticular chapters. A hold'em player reading the book probably shouldn't skip any particular section.
Using the typical cardroom in the US as a reference point, this book includes disproportionate coverage of big-bet and tournament poker. There is certainly plenty of material on other forms, and much of the material is fairly general. But if you have no interest in these forms of poker at all, you might find it tough to sort out what's relevant and what's not.
Since the contrast is so stark, I thought it would be worth mentioning a few of the advantages that this approach to poker writing has over the approach taken by other writers of quality poker literature. First, Ciaffone's approach is anything but cookbook. He encourages reasonable disagreement, but generally provides enough insight into his reasoning to make sure the reader understands the issues involved. Other writers often make a half-hearted disclaimer up front but then couch their texts in more absolute terms.
Second, he includes several chapter-length quizzes that do not merely restate material presented earlier in the book, but actually ask the reader to think through poker situations that span the range from mundane to interesting. In contrast to the quizzes in the Two Plus Two books, which are intended to help readers refresh their memories of the material in the book, the quizzes in Ciaffone's book represent a useful pedagogical strategy for engaging the reader on topics of interest.
Third, Ciaffone invites disagreement. While he makes many points in fairly absolute terms, he also makes it clear that little of his advice is set in stone, and that intelligent players will find opportunities to deviate from the strategies he describes. He also points out instances where other experts might disagree with his advice entirely. In fact, he includes a brief chapter surveying a number of top poker players on how they would handle a particular situation he once faced in a tournament. Only the most passive reader will be able to finish this book without having found something with which to take issue (I personally found his discussion of "advertising" to be too black-and-white).
In short, Ciaffone affords the reader a certain amount of respect, where other writers tend to take a master-disciple trust-me approach. This will be most helpful to readers who prefer to think things through on their own, and to readers who have already read (and understood) a few books on poker.
One down side to this book is that some of the material has been published before. There's no way for me to tell how much - I noticed a section duplicated from his book with Stewart Reuben. That may be it, or there may be more. I would guess that a lot has been borrowed from his columns.
Finally, it would be wrong to review this book without mentioning Ciaffone's writing personality. He comes across (to me) like a quirky but knowledgeable uncle with whom you have a few minutes before the rest of the family arrives. He's not quite curmudgeonly, but there are tendencies that way. The book is peppered with odd expressions - a player who commits the sin of exceptionally weak play seems invariably to earn the "Caspar Milquetoast award for cowardice." The fact that these expressions were not edited out may be a good argument in favor of self-publishing.