In 1965, Helen Taussig traced the evolution of knowledge of congenital heart disease (CHD) during the 20th century, beginning with the William Osler-Maude Abbott lineage at McGill University in Montreal, Canada. Osler encouraged Abbott in her CHD pathologic observations. Abbott's London Exhibit (1934) preceded her classic text Atlas of Congenital Cardiac Disease (1936). Taussig's friendship with Abbott (1935) began in Boston; Abbott brought Taussig to meet Paul Dudley White whose text Heart Disease (1931) featured Abbott's work. Taussig visited Abbott (Montreal 1938). Abbott's statistical approach was based on post-mortem malformations; Taussig's concern was why CHD babies died. Abbott (1927) suggested surgery for a patent ductus arteriosus; Taussig conceived of creating a patent ductus arteriosus shunt to improve lung blood flow in cyanotic “blue babies”. Surgeon Alfred Blalock and Taussig collaborated with the blue baby shunt operations (1944–1945), opening the field of cardiac surgery in cyanotic babies. Taussig's Congenital Malformations of the Heart text came 2 years later. Sequential contributions by Osler, Abbott, White, and Taussig were landmarks in the evolution of knowledge of CHD in North America.