Definition of the barrier The interstitial fluid (rSF) of the brain is separated from the blood by the blood-brain barrier (BBB). This barrier must not be thought of as a single entity or as an absolute restriction to all molecules, but as a multiple structure located at several sites within the brain. The first of these interfaces is located at the endothelium of the brain capillaries. Secondly there is a potential site for interchange on the outer linings of the brain between the dura and the arachnoid membranes. Thirdly, there are the choroid plexuses and the cerebrospinal fluid (CSF)...

The scientific contribution of Mike Bradbury to the study of the blood-brain barrier is considerable and wide-ranging, starting with his M.D. thesis in 1962 and still continuing today. The varied spectrum of topics relating to the blood-brain barrier presented in this volume and the many geographical locations from which both speakers and participants gathered to attend the symposium are a fitting testament both to Mike's wide-spread influence in the field and to the esteem in which he is held. When we first had the idea of afestschrift to mark Mike's retirement as Professor of Physiology at...