109 for 0, Jacqueline!!
I. A. Richards is not himself a theory. Things like poststructuralism and feminism are currents of literary theory. I think that Richards was of the New Critics. The point is that you seem to have the stick by the wrong end: identify the current; then learn its characteristics; and by that time you will have moved from explanatory texts to the seminal essays, which are written by people -- Saussure as lodestone of structuralism, for example.
You don't compare a theory to a book. You use a text, book or otherwise, as material for the bringing to bear of the valules of a current of theory. For example, you might make a feminist analysis of (a reknowned sexist like) Freud.
Don't you have course texts? Raman Selden? Abhrams's DIctionary of Terms, etc.?