The article deals with some untouched problems concerning Shostakovich’s 24 Preludes and Fugues: the three independent lines formed by the subject and its two fixed countersubjects, all on the same triad; the “answer in natural mode” in the same key; and the techniques of “motif growing” and “straight expansion” as concluded by the author. In addition, the followings are also treated: the application of quite a number of musical forms in the polyphonic suite, and the inner link and formal comparison between preludes and fugues.