As a consequence of having reviewed the previous edition of this book in 1985, I was compelled to realize how fast and how far medicine has advanced in less than a decade and how well the authors have documented this progress in the sector of allergy. For instance, in his chapter "Biochemical Mediators of Allergic Reactions," Stephen I. Wasserman brings us up to date on exciting new developments that promise to revolutionize allergy: high molecular weight—neutrophil chemotactic activity (HMW-NCA), leukotrienes, cytokines, platelet-activating factor, arachidonic acid and its associated enzymes, 5-lipoxygenase and cyclooxygenase, and other chemotactic factors. Understanding that there are no clear-cut lines between practical and theoretical, research and dogma, conjecture and fact, and that there is no way of knowing just when a new development will become standard procedure, the authors prepare the groundwork for the "new allergy" of the future while keeping the book germane to the clinician