Along with Aristotle, Gottlob Frege, and Kurt Godel, Tarski is generally considered one of the four greatest logicians of all time (Vaught 1986). Of these four, he was the best mathematician and the most prolific author.

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Hence between 1923 and his departure for the United States in 1939, Tarski not only wrote several textbooks and many papers, **a number of them ground-breaking**, but did so while supporting himself primarily **by teaching high-school mathematics**.

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2007.05.04 CHK2