This guide serves as a portable identification manual for various species of freshwater and saltwater fish found in British and European waters. The authors, Keith Linsell and Michael Prichard, utilize their expertise in natural history to provide a structured reference for anglers and naturalists. The text organizes species by habitat and physical characteristics to facilitate rapid field identification.

The text functions as a compact, utilitarian reference tool designed for high-frequency use in the field. Its concise formatting and focus on visual identification markers suggest a target audience of amateur naturalists and recreational anglers seeking a reliable, pocket-sized resource.