I had bought Clem Lindenmayer's guide back in 1998 before my first trip to Patagonia, so decided to get up-to-date with this edition by Carolyn McCarthy for my trip south in January 2012.
Before even getting off the plane, however, I noticed a few errors that should really have been spotted before going to print.
For example, having Isla Navarino labelled for 2 different locations on the inside cover was not a good start! Then I noticed the climate data on page 229 had Ushuaia with a tropical climate - average max temp close to 30 Celsius - at 55 degs South? Hard to believe!
Down on the ground, however, I found it very useful and generally accurate for the 2 areas I explored; Torres del Paine and Parque Nacional Los Glaciares.
In particular, those trail maps in the guide that I used were clear and a very welcome addition to the maps I acquired locally, although I did think that some depiction of contouring en-route would be useful.
Also, perhaps some of the trail details could have been a little clearer on any technical issues. For example, the Laguna Sucia side trip on page 173 actually requires some scrambling out of the river bed and over a promontory and perhaps this could have had a brief mention?
All in all, though, a welcome companion and I hope to go back to Patagonia next year and do a few more of the routes suggested in this book.