None published between 17th ed. in 1999 and 18th ed. in 2006.
Vols. for 1950- published by Merck & Company; <1972-> by Merck Sharp & Dohme Research Laboratories; by Merck Research Laboratories, 1999-
Also issued 1987- as two soft cover vols: Merck manual of diagnosis and therapy. Volume I, General medicine; and: Merck manual of diagnosis and therapy. Volume II, Gynecology, obstetrics, pediatrics, genetics.
Latest issue consulted: 20th ed., published in 2018.