Encyclopedias, Almanacs, Transcripts, and Maps
- Medieval Kinematics
- Medieval Magic
- Medieval Religion, Science, and Astronomy
- Medieval Trade Fairs and the Commercial Revolution
- Medifast
- Meehl, Paul E(verett) (1920-)
- Meerloo, Joost A(braham) M(aurits)(1903-1976)
- Megalencephaly
- Meghnad Saha
- Meier, C(arl) A(lfred) (1905-)
- Meier, Eduard Albert "Billy" (1937-)
- Meisner (or Mesna Lorentz) (ca. 1608)
- Melissus of Samos
- Mellon, Annie Fairlamb (Mrs. J. B. Mellon) (ca. 1850-ca. 1938)
- Melodic Intonation Therapy
- Melton, J(ohn) Gordon (1942-)
- Melusina
- Melvin A. Fisher
- Melzer, Heinrich (1873-?)
- Membrane Fluidity