Relevance Logic and Entailment

Note carefully that the title of this piece is not ‘A Survey of Relevance Logic’. Such a project would be impossible given the development of the field and even the space limitations of this Handbook. For example Anderson and Belnap’s [1975] book Entailment: The Logic of Relevance and Necessity, volume 1 runs over 500 pages, and is their summary of just ‘half’ of the work done by them and their co-workers up to about the early 70s.1