This chapter describes the origins of probability theory, including the considerations of Monsieur de Baussay, vel Antoni Gombauld, best known as Chevalier de Mere on the “the banker’s number”—the number of experiments where the odds shift from being favorable to the player to being favorable to the banker. We also review the basics of combinatorics starting from the multiplication principle and progressing through permutations, variations with and without repetitions, and combinations up to the problem of placing distinguishable or indistinguishable balls in distinguishable or indistinguishable urns. This latter problem is important in statistical physics (see Maxwell-Boltzmann statistics and Fermi-Dirac statistics).