This book is based on contributions presented at the symposion "The Primary Afferent Neuron: A survey oj recent morpho:functional aspects. H held in Zurich on March 24th. 1988 in connection with the 83rd Congregation of the German Anatomical SOCiety. Members of the Anatomical Society as well as non-member researchers were invited to join a circle of specialists to discuss the topiC of primary afferents. In addition. some aspects which had not been dealt with at the Symposion because of shortage of time are represented by invited reviews included in this volume. As sCientific research on the primary afferent neuron is so extensive. it is impossible to take inventory of all the present activities on this subject. This book attempts to provide an overview of various aspects of high actuality and. in particular. shows how morphological research contributes to our present -day concepts of the primary afferent neuron. Although fundamental knowledge on morphology and physiology of the spinal ganglion cell seems to be well established. many questions of the past and the present still await conclusive answers. Thus. many question-marks deter­ mine the conceptual layout of this book (Fig. 1): First. the peripheral sensory field. and. in particular, the peripheral sensory receptors are discussed.