A ‘provisional description’ of the alcohol dependence syndrome was first given in 1976. An outline is provided of the historical background to the syndrome formulation. Ideas emanating from the Maudsley campus were important but so was the international input from a WHO Scientific Group. Since its original delineation the syndrome idea has attracted discussion and has become a focus for research. Studies which bear on the measurement and validity of the syndrome concept are summarized and criteria for the establishment of validity discussed. Understanding of the nature of this condition is still incomplete but research has now reached a stage where it is legitimate to go beyond the question as to whether a dimensional syndrome exists, to an exploration of theoretical questions relating to its scientific basis. Further elucidation will require contributions from many different disciplines. The syndrome can offer part of the explanation of why some people continue to drink too much in the face of negative consequences but measurement and conceptualization of this one dimension should help toward the design of more powerful, multidimensional and interactive models. A plea is made for a spirit of openess and interdisciplinary enquiry rather than perseveration with the unproductive rhetoric of the ‘disease’ debate.