No doubt the Queen, with her training, could comprehend all the impossible problems in the natural sciences that are being solved nowadays. Others of us find our heads spinning when we try just to keep up with the endless flow of facts and theories. So many new concepts and methods are emerging, in fact, that one js sometimes tempted to follow the advice of the charlady who counseled her friend, “Take things philosophically, dearie, just don’t think about ‘em.” But in our less favored world it is impossible to ignore the rapidly accumulating knowledge. It is equally impossible to encompass even a fraction of it. No one can be competent in pathology, biochemistry, immunology, electron microscopy, and the other special fields whose combined skills and insights are often needed to attack a single biological problem. And the horns of this dilemma are particularly sharp; too close concentration within a small area means myopic vision, while the oppositespreading one’s attention over a large area-invites such dilution as to preclude any real depth of knowledge. What, then, is the best approach to a problem in medicine where the talents and experience of several disciplines are necessary? The obvious solution, and probably the only practical one, is the team approach, whereby, hopefully, depth of investigation joins with and complements wide scope. The drawbacks are expense, problems of communication, and the fact that co-workers tend to waste each other’s time. In our laboratory, two problems have been of particular interest: the cause of arteriosclerosis and the cause of fever. From the outset, investigation of each problem necessarily called for the team approach; work had to start simultaneously with biochemistry and electron microscopy, and none of us was adept in both fields, and most of us in neither. Recently, after a year’s work, we have scrutinized our studies of the pathogenesis of fever-what they had accomplished and, more particularly, where they were headed. Others before us have pondered the mysteries of the febrile process. The ancient