Nadia Boulanger was the most important composition teacher of the 20th century; perhaps it would be better to say music teacher, as her pedagogical credo was to “understand others”, to “make students express themselves”. From the age of 16 until old age, she is said to have taught more than 1,000 pupils. The violinist, writer and filmmaker Bruno Monsaingeon, who later made a name for himself with documentaries about Glenn Gould and Sviatoslav Richter, among others, observed Nadia Boulanger teaching and released this film in 1977 to mark her 90th birthday. Igor Markévitch and Leonard Bernstein also have their say here with memories of “Mademoiselle”.