When ever I am getting into a new topic I try to start with OUP's Very Short Introduction series [0]. They generally do not give good understanding but they orient you in the field and provide extensive bibliographies along with the knowledge required to navigate that bibliography and select the sources which will give you the information you desire instead of what someone else thinks you want. Failing that I just go down to the library and talk to the librarian.

0: https://global.oup.com/academic/content/series/v/very-short-...