This text on the art of "cytologic aspiration biopsy" is a summary of Dr. Nils Soderstrom's personal experience gathered in performing over 6,000 aspiration biopsies. In his introduction, the author outlines the limitations of the technique, stating that "disappointments may be avoided if the clinician is prepared not to regard all biopsy reports as final diagnostic oracles." The author apparently is aware of the lack of acceptance of this diagnostic aid and writes, "The attitude in some centers to cytologic biopsy may be expressed simply in the sentence: it is an easy method of obtaining incomplete and sometimes unreliable information." Unfortunately, the present text doesnotpresent convincing evidence that this approachisreliable or useful. Except for "serous effusions" and "mammary gland aspirates," the author does not giveanysupportive data to correlate with his findings on cytologic biopsy. Thus, for example, the recitation of results in 500 consecutive