Pharmacology， for the purpos~ of this book， is<br > considered to be the body of information that underlies<br > the effective and safe use of drugs ~the diagnosis，<br > prevention， or treatment of disease. Plowever， phar-<br > macology includes many controversial areas， and<br > opinion begins to diverge with the very definition of<br > the field. From the point of view of the practicing<br > physician and medical student rather than the research<br > specialist， pharmacology is a derived or applied sci-<br > ence. Understanding how drugs are used and progress<br > in drug therapy require the application and develop-<br > ment of special information from many areas， espe-<br > cially organic and analytical chemistry， biochemistry，<br > physiology， and the various clinical specialties.<br > Many research- and laboratory-oriented phar-<br > macologists prefer to regard pharmacology also as a<br > basic science and view it as a valid field of investiga-<br > tion independent of its immediate applications. Their<br >approach would emphasize some of the headings in the<br >outline below and minimize others. The emphasis of<br >this book reflects the teaching responsibility of phar-<br >macologists toward students in the professions rather<br >than the needs of research pharmacologists. It deliber-<br >ately blurs any distinction between pharmacology and<br >therapeutics.<br > The discussion of most of the groups of drugs in<br >the following chapters of this book is organized ac-<br >cording to the outline that begins below. However，<br >several chapters on general pharmacologic or<br >therapeutic subjects precede the chapters in which the<br >drug groups are discussed. Whether these general<br >discussions should be read before or after a store of<br >specific pharmacologic information is acquired de-<br >pends upon the individual student. The following brief<br >review of the conventionalized outline of what a prac-<br >titioner should consider before using a particular drug<br >should allow study of the general chapters to be de-<br >ferred if desired.<br ><br >