Cholesterol is one of the most important molecules in the body, as well as the most important steroid. As Brown and Goldstein put it in their 1985 Nobel Lecture, “[Cholesterol is] the most highly decorated small molecule in biology. Thirteen Nobel Prizes have been awarded to scientists who devoted major parts of their careers to cholesterol”. All steroids have four carbon rings fused together in a similar geometry (5.1); three of these are six membered and one is †ve membered.