We obtained a copy of Breeding and Bansmer's invaluable cruising guide before we arrived in Mexico.
When we left the US we could not imagine how bad the official charts are in Latin America. The official charts are often over a century old. The Latitudes and Longitudes of major features are often incorrect by a nautical mile or more. And the minor features are depicted poorly, important anchorages often do not warrant the faintest wobble of the cartographer's pen. In short, it would not be prudent to rely on the for-navigation charts while cruising Mexico. And the electronic charts are just copies of the for-navigation charts, obvious multiple-mile GPS errors and all.
Luckily there are accurate charts of Mexico. Breeding and Bansmer have painstakingly combined data from NASA satellites and their own GPS and depth sounders to produce useful, high quality charts of the anchorages and their approaches. For this reason alone this book is a must for cruising boats.
This guidebook is also well written and beautifully finished. I none of my other guidebooks approach its high publication quality. I'd recommend it even if it wasn't for the appalling condition of the official charts, just for its descriptions of anchorages and other cruising advice.