On a recent holiday I checked out 3 guidebooks to walking on La Gomero, and though I have no experience of El Hierro (and therefore comment only on La Gomero content) I believe I am in a position to endorse this Cicerone publication as probably the best - especially for those seeking more arduous outings rather than rambles. As common with many Cicerone guidebooks there are brief notes on geology, wildlife, history, language, health and safety etc. as well as best times to go, how to get there, accommodation, food and drink etc. plus useful contacts (up to 2011). However unlike many Cicerone publications `Walking on La Gomera and El Hierro' comes as a paperback rather than more usual plastic covers, but it is well made and put up with rough treatment.
Unfortunately the Cicerone guide does not specify grades for routes but it gives a satisfactory description of the terrain to be encountered together with distance, ascent/descent and average time, plus start finish points, transport services and refreshment opportunities. Maps are diagrammatic but adequate for planning, and I supplemented guidebook information with a 1:35,000 scale map. It would be nice to be able to report how walkers may rely on the guidebook claim that all selected routes are fully signposted and waymarked but my limited experience suggests otherwise. However paths are generally good and I can confirm that piecemeal directions and landmarks are accurately detailed. There are 27 routes described on La Gomera and a further 18 on El Hierro. Of the 27 on La Gomera there are 18 that more or less overlap with walks suggested in other guidebooks and they embrace the full flavour of the island using a variety of centres, plus 9 long distance `gran recorrido' routes. There are 7 stages of GR132 around the island, and 2 stages of GR131 across the island.