Rav Israel Salanter's and Musar [learning books on Ethics]. Learning the books of Musar tends to give a different impression of what Torah is about than what one would assume. Without Musar the tendency is to imagine Torah being about all kinds of things that it really is not. Even though that can exist even inside of Litvak yeshivas where Musar is learned, still the tendency is a lot less.
That is to say that Musar more or less defines the major emphasis of Torah as being about Love and Fear of God and good character traits. And it goes at length into defining what is good character. Since that is not at all obvious not easily apparent to pure reason, there is a need for Musar.
Why is it that Musar [books on ethics written during the middle ages] does a better job of this than later books is not clear, still the fact is that later books that are claiming to show what Torah is about are usually just examples of religious fanaticism and insanity, --the result of schizoid personalities.
[Musar refers to a small set of books written during the Middle Ages, but also can include the books of the disciples of Rav Israel Salanter or the Gra.]
[The idea of Musar is predicated on the more general idea of Litvak Yeshivas that the Rishonim [medieval thinkers] define what Torah is all about.]
