An obituary for Jan Oort, astronomer axtraordinaire and leader of Dutch astronomy since the 1920's has appeared in the Publications of the Astronomical Society of the Pacific, Vol. 105, pp. 681-5 (by A. Blaauw and M. Schmidt). An excellent collection of papers on Oort's life and work is found in Oort and the Universe, edited by H. van Woerden, W. N. Brouw, and H. C. van de Hulst (1980). An autobiographical article is available in the Annual Reviews of Astronomy and Astrophysics, Vol 19, p. 1 (1981). An exhaustive catalog of the holdings of Oort's archives at Leiden University is The Manuscripts and Correspondence of Jan Hendrik Oort by J. K. Katgert-Merkelijn (1992).