Thomas Bayes, from whom Bayes theorem takes its name, was probably born in 1701, so the year 2001 marked the 300th anniversary of his birth. This biography was written to celebrate this anniversary. The current sketch of his life includes his family background and education, as well as his scientific and theological work. In contrast to some, but not all, biographies of Bayes, the current biography is an attempt to cover areas beyond Bayes’ scientific work. When commenting on the writing of scientific biography, Pearson [(1978). The History of Statistics in the 17th and 18th Centuries… . Charles Griffin and Company, London] stated, “it is impossible to understand a man’s work unless you understand something of his character and unless you understand something of his environment. And his environment means the state of affairs social and political of his own age.” The intention here is to follow this general approach to biography.
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There is very little primary source material on Bayes and his work. For example, only three of his letters and a notebook containing some sketches of his own work, almost all unpublished, as well as notes on the work of others are known to have survived. Neither the letters nor the notebook is dated, and only one of the letters can be dated accurately from internal evidence. This biography contains new information about Bayes. In particular, among the papers of the 2nd Earl Stanhope, letters and papers of Bayes have been uncovered that previously were not known to exist. The letters indirectly confirm the centrality of Stanhope in Bayes’ election to the Royal Society. They also provide evidence that Bayes was part of a network of mathematicians initially centered on Stanhope. In addition, the letters shed light on Bayes’ work in infinite series.