Steps towards higher mathematics
Set theory is the foundation stone of the edifice of modern mathematics. The precise definitions of all mathematical concepts are based on set theory. Furthermore, the methods of mathematical deduction are characterized by a combination of logical and set-theoretical arguments. To put it briefly, the language of set theory is the common idiom spoken and understood by mathematicians the world over. From all this it follows that if one is to make any progress in higher mathematics itself or in its practical applications, one has to become familiar with the basic concepts and results of set theory and with the language in which they are expressed.