The shortage of qualified secondary school mathematics and science teachers is discussed and a program is described which aims to lessen the severity of this dilemma. The MidCareer Mathematics and Science Program (MCMS) at the Harvard Graduate School of Education demonstrates that quantitatively trained individuals with extensive knowledge of mathematical and scientific applications can provide an alternative supply of highly qualified classroom teachers. The program awards either a Master's degree or a Certificate of Advanced Study and secondary teaching credentials in the fields of mathematics, physics, chemistry, biology, and/or general science. Classes are conducted during the academic year with optional summer study workshops. The program has attracted individuals from diverse backgrounds and careers including a rear admiral, a public defender, a meteorologist, and several higher education professors. Profiles of the program's participants are given and the teacher characteristics of academic talent and entry motivation are discussed. The motives of the mid- or late career professional are also compared and contrasted with younger teacher candidates. (ML)