Alfred Tarski made considerable contributions to several areas of mathematics, including set theory and algebra, and his work as a logician led to important breakthroughs in semantics--the study of symbols and meaning in written and verbal communication. Tarski's research in this area yielded a mathematical definition of truth in language, and also made him a pioneer in studying models of linguistic communication, a subject that became known as model theory. Tarski's research also proved useful in the development of computer science, and he became an influential mentor to later mathematicians as a professor at the University of California at Berkeley.

Born Alfred Tajtelbaum in Warsaw, Poland (then part of Russian Poland), on January 14, 1901, Tarski was the elder of two sons born to Ignacy Tajtelbaum, a shopkeeper of modest means, and Rose (Iuussak) Tajtelbaum, who was known to have an exceptional memory. During his teens Tarski helped supplement the...