chopin was greatly influenced by johann sebastian bach when he wrote these preludes. each of the works in the collection is in a different major or minor key, with not one being left out, just like bach's 24 preludes and fugues in "the well-tempered clavier". but unlike bach, chopin arranges the preludes in order through the circle of fifths. the first prelude in the set is in c major, the next in a minor, then g major, e minor, and so on, until the last two, which are in f major and finally d minor.