Literary theory offers different approaches for studying and analyzing literature. There are many schools of literary theory (for example, Marxism, feminism, ecocriticism, decolonial theory, etc.), and any work of literary criticism [...] may employ one or more of them (Mt. Holyoke LITS)." You can find books / eBooks and journal articles that explain literary theories, as well as books and journal articles that apply theory or theories to a literary work, which is literary criticism.