 Bernoulli 's work , originally published in Latin is divided into four parts . It covers most notably his theory of permutations and combinations ; the standard foundations of combinatorics today and subsets of the foundational problems today known as the twelvefold way . It also discusses the motivation and applications of a sequence of numbers more closely related to number theory than probability ; these Bernoulli numbers bear his name today , and are one of his more notable achievements . 
