Born in Paris in 1894, Suzanne Briet was active nationally and internationally in the development of what was then known as Documentation but would now be called Information Management or Information Science. In 1931, she participated in founding the Union Française des Organismes de Documentation (UFOD), the French analogue of the American Documentation Institute now called the American Society for Information Science and Technology. She was a leader in developing professional education for this new specialty and designed a plan for what would have been the first school of Documentation / Information Science worldwide, had it been established. In 1951, when a school of information science was finally established, Briet was the founding Director of Studies. She became Vice President of the International Federation for Documentation (FID) and acquired the nickname 'Madame Documentation.' What is Documentation? relates this fascinating story and includes the first English translation of Briet's remarkable manifesto on the nature of documentation, Qu'est-ce que la documentation? (Paris: EDIT, 1951). A pamphlet of 48 pages, Part I sought to push the boundaries of the field beyond texts to include any material form of evidence ('Is a living animal a document?' she asked). Part II argued that a new and distinct profession was emerging. Part III urged the societal need for new and active documentary services. This tract remains significant due to its continuing relevance towards understanding the nature, scope, and societal impacts of documents and documentation. Briet's modernist perspective, combined with semiotics, deserves attention now because it offers a sturdy and insightful alternative to the scientific, positivist view that has so dominated information science and which is increasingly questioned.