This small book, volume 608 in the "American Lecture Series," is a "review of current knowledge regarding malignant cells in circulating blood." It is indeed a conscientious and fairly complete survey of the writings of those since 1829 who have wondered about the mechanisms of spread of tumor cells, and of those since 1955 who have struggled to develop techniques of isolation and recognition of tumor cells from blood samples. It is, on the whole, a faithful representation of the confusion which presently reigns in this field.
There is little conscious attempt to separate speculation from findings, and some nonchalance regarding the validity of reports of various authors. It is helpful in evaluating this work to learn that part of it was submitted as a thesis for the degree of MD at Cambridge. This explains a certain quality of innocence with regard to pathology, the precise morphologic criteria of malignancy