His industry and genius have left a permanent impression in every field of mathematics; and although his contributions to the Theory of Probability relate to subjects of comparatively small importance, yet they will be found not unworthy of his own great powers and fame.

Isaac Todhunter on Leonard Euler [1]

Biographies of Leonhard Euler (1707-1783) are widely available; Dunham [3, pp. xix-xxviii] and Calinger [2, pp. 486-489] have excellent lively accounts, while the *Dictionary of Scientific Biography* [4, pp. IV.467-484]DSB has a longer and more scholarly entry. Euler published over 30,000 pages of mathematics and physics, currently available in the 74 volumes of the first three series' of his *Opera Omnia*[5]. Volume 7 in Series I of the *Opera Omnia* is probably one of the most often consulted volumes of the entire series, because it contains papers on a variety of well-known mathematical problems, including the Bridges of Königsberg, the Knight's Tour, Magic Squares, the problem of Derangements and the Josephus Problem. However, these gems of recreational mathematics are to be found nearly buried among the more prevalent subject matter of this volume: some two dozen entries concerning probability theory and related subjects.

"Towards the middle of his life," wrote Louis Gustave du Pasquier, the editor of volume I.7, "Euler devoted a portion of his universal interest to the study of the theory of risk and ¼ to questions involving the calculus of probability [6, xxiii]." Alongside articles on observational error, mathematical statistics and the foundations of life insurance, volume I.7 contains eight memoirs and a fragment concerning probability theory on finite sample spaces. All of these are inspired by games of chance, be it the casino game *Pharaon*, the card game *Rencontre*, or the well-known Petersburg Problem. However, the greatest portion of Euler's writings on probability theory relate to the Genoese lottery.