Bibliography. The already voluminous world cancer literature is increasing at the rate of about 5000 references annually. We feel that any attempt to do justice to even a representative portion of these would run counter to the avowed purpose of this book. Furthermore, most of the material in this book stems from the experience of Strang Cancer Prevention Clinic where over 100,000 patients have undergone some 360,000 cancer detection examinations in the twenty years since its founding. The interested reader is directed to the source material at the end of the book where a selected list of sources will provide him ready access to whatever he wishes to pursue in further detail.

Arguments. What has been emphasized in these pages is that which is universally acknowledged or about which it is possible to reach some concensus. Where a significant controversy exists, this is acknowledged, but whenever possible we have set down our own or the majority opinion. Rather than a tedious recital of details, arguments, and exceptions to rules, we have attempted to provide a point of view which is useful in practice.

Details of pathology. Only where such seems necessary to the doctor's understanding of the problem or its management have these been presented beyond the bare essential facts.

Details of x-ray features. Representative x-ray films of pertinent sites have been included for background purposes. It is our conviction that whenever the x-ray diagnosis is other than obvious, the opinion of an experienced radiologist is mandatory.

Differential diagnosis. In the discussion of cancer in each site pages could have been devoted to the differential diagnosis of the lesions. Almost without exception, however, cancer is the one lesion you cannot afford to miss. It is far more important than other lesions with which it may be confused clinically. Therefore, an attitude of "cancer until proved otherwise" (by biopsy, cytology, or surgical exploration) is our dictum.

Treatment. To have introduced the principles and details of treatment would have doubled the size of this book. Included, however, are some of the steps in the immediate management of certain cancers, and here diagnosis and treatment are often hard to separate.

Prognosis. It is almost heretical to propose a book on cancer without the cherished, conventional tabulations of five-year survival rates. These massed armies of statistics are, to the uninitiated, seldom clear, often dull, and rarely helpful. Furthermore, as Sir Heneage Ogilvie once remarked, they are often "either too good to be true or too true to be good."

In any event, for the average physician concerned with the care of the individual patient, such figures may provide an all too uncertain reference point.

One other item must be dealt with. That is the important question of how far the practitioner should carry his own personal management of a case. To the point of suspicion? To the point of diagnosis? What diagnostic procedures should he carry out, and what should he rely on others for? Should he carry out any treatment?

These are questions to which the practitioner has long since provided his own personal answers. Since there are so many imponderables such as the doctor's own interest, training, experience, competence, and time (as well as availability and reliability of private and community facilities), no single answer is possible. Only the reader can decide where his responsibility begins and ends.

Once again, we must repeat that it is the first physician who sees the patient who is the key to the whole problem. Acquaintance with and application of the techniques of cancer detection, diagnosis, and prevention to be found in this book cannot fail to result in an improved prognosis for many patients with malignant and premalignant disease.

Walter E. O'Donnell Emerson Day Louis Venet.