Recombinant human interleukin-2 became available for clinical use in the mid 1980s. Recent years have seen an enormous amount of clinical research with this cytokine and interleukin-2 has now been registered for use in a number of European countries for the treatment of metastatic renal cell carcinoma. This book is designed to provide the clinical oncologist wishing to use interleukin-2 with a basic background concerning the biology of the agent, a discussion concerning practical aspects, of its clinical use including management of toxicity and an overview of the clinical results together with a description of how this interesting cytokine might be developed in the future.