Since 1985, Synopsis No. 31 has been the standard work in English, providing the only generally-available means for correctly identifying earthworms and the easiest source of information on their biology and ecology. However, there have been few recent developments in this science so that, when stocks of the first edition began to run low and a second was considered, it was apparent that the few alterations required – rather less than two sides of A4, plus minor typographical errors – did not really justify the title of Second Edition. As it seemed important to retain Earthworms 'in print' a 'Revision' has been prepared.