Postnatal simultaneous inactivation of p53 and Rb1 tumor suppressors results in reproducible initiation of ovarian epithelial carcinogenesis in mice homozygous for conditional gene alleles. Histologically, ovarian tumors range from serous adenocarcinomas with cysts and papillary structures to poorly differentiated neoplasms. These tumors form ascites, disseminate intraperitoneally, and metastasize to the contralateral ovary, the lung, and the liver. The cover features mouse survival (inset) and an overview image of a representative H&E section of the ovarian serous cystic adenocarcinoma. For details, see the article by Flesken-Nikitin et al., on p. 3459 of this issue.