The thesis is simple and not new. A mass in the child's abdomen can be accurately located by radiologic examination. Conventional, plain film study is used first. Barium gastrointestinal study and enemas, excretory and retrograde urography, and intravenous cholangiography follow if needed. These examinations, affording observations of the size of the mass, its contour, variation with change in position, presence of calcification, or other internal characteristics, can then be correlated with the clinical and laboratory findings and the sex and age of the patient to give an accurate diagnosis in the light of statistical probability. The more complicated less readily available radiographic techniques, such as presacral gas inflation and aortography, are only rarely needed. Simple and as obviously worthy as this thesis of Drs. Nice, Margulis, and Rigler may be, it needs reiteration. They have written a book limited in scope, yet their coverage of their subject is complete. Necessary