Notebooks and notes, reprints, correspondence, bibliographies. The bulk of the collection consists of notebooks and notes on the work of M. Brillouin and his colleagues on meteorology, global wave theory, and electricity. The reprints are by M. Brillouin (1892-1938) on subjects including meteorology, mathematical physics, wave theory, and hydrodynamics; the reprints by colleagues (1879-1944) are on hydrodynamics, oceanography, and tidal research. The correspondence (1887-1939) is both professional and personal, many centered on his research on tides and physics of the earth. There are several letters from his son, Lǒn Brillouin, concerning both physics and family matters. One file contains correspondence between Brillouin and H. A. Lorentz from 1911 regarding Marie Curie and Paul Langevin. The bibliographies include an annotated bibliography of M. Brillouin's published works, as well as a checklist of his public speeches. Correspondents include: Alfred Basset, Lǒn Brillouin, Lord William Thomson Kelvin, Augustus E. H. Love, Max Planck, Arnold Sommerfeld, and Rolin Wavre.