Interferon has been and continues to be one of the more fas cinating substances produced by apparently all animals in response to particular stimuli. It has led to major revisions in concepts of cellular immunity and theories on the recovery of multicellular systems from viral infection. Since its discovery, interferon has held the interest of the molecular biologist, and definitive answers as to its clinical value are close at hand. The following treatise is an attempt by the authors to pre sent a complete picture of the many aspects of interferon. Having recently had the privilege of...