This article explores 3 aspects of breast diagnosis that are currently under investigation and about which our thinking has recently undergone considerable reshaping. The trend toward more frequent evaluation of clinically subtle lesions has suggested that it might be necessary to understand thefine-needle aspiration (FNA) presentation of proliferative breast disease. Efforts to do so, as well as our suggestions for additional studies and their potential limitations open this discussion. Following this section, the increasingly useful method of intraoperative cytology for evaluation of resected breast masses is considered in detail. In the final section, optimization of nonoperative sampling by combination of mammography, ultrasonography, fine-needle aspiration, and core biopsy is discussed and illustrated.