Neil McDonald is one of the most prolific chess writers in the new millennium. His target audience is typically the new to middle of the road club player who just doesn't have the insight into positional mistakes linked with a medium-depth strategy. Although McDonald is a talented writer, this book really brought out his biggest shortcomings. The book is "repertoire-like", but many alternatives are either dismissed, omitted, or simply treated at a superficial level.
So, with that introduction, why as many as three stars?
This is the second complete book on the Reti that I've completely worked through (not counting the collection of Reti's games, but I'll comment on why that isn't really all that applicable for a book on the Reti). The first was Davies book "Dynamic Reti" which is a better book for looking at more lines and alternatives, but was clearly lacking in providing strategical insight. The Reti is a difficult opening because of all the transpositions that BOTH sides can elect. So, a big part of the strategy in the Reti is to make decisions to get a persistent but small initiative. The ideas in the Reti are much better explained by McDonald and perhaps I needed more of a beginner's perspective on some of the lines where GM games simply do not obviously lead to clear positional assessments. At least in McDonald's book, he helps explain the considerations for positional assessment. I should also point out that McDonald heavily leans towards selecting lines that are queenside attack themes. Meaning, ideas associated with pushing c4,b4 followed by additional pawn moves such as b5 or a4,a5. The tricky part of the Reti is that this strategy is simply bad when the opponent plays in the center, but in that case, the experienced Reti player knows when to switch to a center strategy. To complicate things, there are some lines that emphasize f4. So, if it isn't obviously already, the Reti is all about constantly assessing the position to find the modest advantage for white. So, really the three stars is for the strategic insight that is the "starter" ideas and strategies for the Reti.
Words of caution ...
if you're a fairly experienced/skilled player at the advanced club level, this book probably is too remedial and you might find a more complete repertoire in Davies' book. If you're a beginner, this book (and the selection of the Reti) is problematic because of all the transpositions and the types of positions that you'll need to learn to play just to get started. Based on these two statements, you might get the idea that I'm saying that the target audience for this book is EXTREMELY narrow. The only way to learn the Reti (really) is playing games and using the material as a reference to see where you started to make mistakes (strategically and even sometimes tactically). Not to mention, one of the dangers of the Reti is that missing one key moves is the difference between a good game and a rotten game. This is exactly the reason that some highly skilled players like it. With that said, I've played this a number of times on the internet and always get a playable and interesting game. I have some really nice wins and some really embarrassing losses. The richness in ideas is the reason that I like it.
Other material on the Reti ....
Reti's best games by Golembek is an excellent game collection but only has a handful of truly Reti games in it (probably less than 5). So, you'll see the history of the opening, but certainly not enough to really get started. Note: I will give McDonald some credit for including very current games with limited analysis. Watson's book (volume 4) is extremely limited and simply provides interesting but not comprehensive material. But Watson is a very good writer and analyst so it's worth at least taking a look at his info on the Reti. But you won't learn the Reti from Watson's book. There is a new book that I have not read (Wojo's Weapons) that also proposes a Reti setup, but at this point, it doesn't look promising enough to invest the money and time.
In summary ....
The pros for this book is that it addresses a gap in explaining strategical ideas in the Reti with the insight from a GM with a lot of writing experience (and talent). It's not a terrible way for getting a "feel" for what to do in the Reti, but again, advanced players will likely leave wanting more critical analysis (this may be found in Khalifmann's book on Kramnik and the Reti, but these books are not that available but could be a good source for advanced players.) The book is very readable and has enough diagrams to avoid playing through every game on the board (although some games had 10 - 20 moves without a diagram and that simply is too many moves for me to visualize without getting position updates).
The cons are fairly extensive, the chapter on the English is such a weak attempt that the author would have been better served referring to other books. It is almost unusable material because of the lack of depth, lack of discussion on transpositions, and quite honestly a presentation that does look like he was "filling out the book". It was illustrative of the problem with the Starting Out series. They simply can't address complicated openings in a responsible way. The hope is that they give the reader a push in the right direction followed by a whole lot of self-study. This is the most exaggerated case for this problem due to the nature of the Reti. McDonald makes a decent attempt, but you could tell that he was meeting a deadline using a great deal of ideas from his books that deal with strategy etc.. I also don't like the quality of these books. The layouts are awkward and one gets the idea that they are too formula-like. (Note: One example of a book that is the gold standard for chess opening is Shipov's Hedgehog book. I even favor his book slightly over Marin's work and I think Marin is fabulous).
Overall, it's hard to recommend this book but given that the selection of books on the Reti is so lacking, it might be the best choice for the player who is of decent playing strength that wants to improve his decision making in the Reti. Beginners probably should stick to playing e4,d4 until they learn other basic strategical ideas (but that's just my opinion).