This book is a great help for finding tricks to learn kanji characters more quickly. However, I don't think it's sufficient on its own to really complete learning these characters.
The book is divided into two parts; Part I is a repertoire of around 250 "graphemes", kanji "pieces" that are used to build up actual kanji characters, but may not necessarily form characters of their own. If that sounds like the definition of a "radical", well good: they're closely related. However, there are various graphemes that are not officially considered radicals, so you might consider the graphemes to be a superset of the radicals.
Each grapheme is associated with an english word or phrase. The book is fairly careful to use different words for very similar meanings, so that you can manage to keep them separate.
Part II is a list of two thousand kanji characters, ordered in such a way as to make full use of the graphemes learned. The kanji are ordered so that the characters only use those graphemes that have already been introduced in the associated group from Part I. Each character is listed along with only its very most common readings (kun and on), and a list of the english words representing the graphemes from which it has been built (which appear in an index at the back of the book).
The book is intended to be used in one of two ways: one way (the way I've chosen to use it) is to learn all of the graphemes in Part I (or at least a large number), and then use Part II to look up characters you wish to learn, and see which graphemes it is made up of. Of course, in reality, you wouldn't normally need to look them up to begin with if you know all the graphemes: you'll recognize them in the characters themselves.
The other way this book is intended to be used, is to systematically learn all the characters of Part II, by learning one group of graphemes, and then studying all the characters from Part II for that same group (which will be ordered appropriately). According to the preface, this is the "ideal" way to use the book. However, I don't really see that as practically possible, without the use of a more detailed kanji dictionary (such as The Kodansha Kanji Learner's Dictionary. Because, for on readings, you can't really get a feel for a character without seeing in what compounds it appears, and how; and learning kun readings can be very misleading, since often a single adjective (atatakai) or verb (hajimeru) may be written using multiple alternative kanji, depending on the context and subtle differences in meaning that are intended. Thus, Kanji ABC might be adequate by itself to learn to _read_ the most common cases where these characters appear, but is quite inadequate for learning when to _write_ them.
The nice thing about this book is that it provides just the tools you need to help grasp the components of a given kanji character, and little else. It doesn't bog you down with _why_ these components have been associated with a given meaning. In the end I think this helps you to learn them more quickly. Other books that may focus more on a character's etymology (such as A Guide to Remembering Japanese Characters (Tuttle language library) (Japanese Edition) can be very enlightening, but in the end they tend to just confuse, as the original etymology of the characters can often have little to do with the modern form and meaning. On the other hand, the trade-off is that you often don't get the "true, original meaning" of a radical or grapheme, just the one that makes it easiest to combine it with other graphemes to learn a kanji.