Steroid Biochemistry, Volume 688 in the Methods of Enzymology series, highlights new advances in the field, containing chapters on a variety of timely topics, including Cytochrome P450 Enzyme, Steroidogenic P450s (CYP11A1, 17A1, 21A2, 11B1, and 11B5), Steroid 17 alpha-hydroxylase/17,20-lyase (Cytochrome P450 17A1), Enzymes of Estrogen Biosynthesis, Aromatase and Steroid Sulfatase, Estrogenic 17b-Hydroxysteroid Dehydrogenase, Hydroxysteroid Dehydrogenases (HSD), 3a-Hydroxyssteroid Dehydrogenase, Approaches to Measuring 3b-Hydroxysteroid Dehydrogenase Type 1, 3b-Hydroxysteroid Dehydrogenase Type 2, and much more.