In response to network requests for advice on how to produce good extension materials, this paper reviewed more than 170 field guides from around the world, ranging from highly technical handbooks to short illustrated pamphlets, variously intended for land users, field staff, project managers, trainers, schools and researchers. Presenting examples of summarised texts, the author discussed, among other things, alternative structures for field guides (e.g. calendar or toolbox), the use of illustrations, what subject matter was available and what not, and how extension materials could be better tailored to their audiences. An annotated bibliography of all the reviewed items concluded the paper.