This is an edited version of an article by A.R. Hewitt which first appeared in The Indexer in Autumn 1963 and was re-published in The indexer in 2014. The editor of LIM felt that the article deserved a wider audience and is grateful to The Indexer for allowing it to be reproduced here*. Although contemporary indexers do not have to trouble themselves with the layout of index cards, much of the advice contained in it is still applicable a half-century later. It is concerned with English law, but again, many of the principles apply to indexing works on legal subjects for other jurisdictions.