The term `local network' first began to appear in print as long as ten years ago. In the second half of the 1970s there was a great deal of interest in techniques for implementing this type of network, namely to link together computers over a restricted area at low cost and at high data rates. It is now becoming apparent that two local network architectures in particular will become internationally the most prominent: these are the Ethernet and the token ring, both backed by US and European standards bodies and by competing and large industrial interests. A token bus is also being adopted for standardisation but seems likely to be in a somewhat secondary role. In the UK the Cambridge Ring, a slotted ring architecture, has made its own impact, but its future appears limited in a wider context. Nevertheless a large research and development effort is associated with the Cambridge Ring and has resulted in a set of UK local networking standards. The purpose of the paper is to give an introduction to each of these local area network structures, particularly by means of their associated standards. A comprehensive list of references is provided as a basis for further reading into the subject