You have to read Unamuno. If he never come up in your literature classes (in Spanish), then your teachers are at fault. He is a classic. Borges, for example, acknowledges his literary and philosophical debt to Unamuno.

La Niebla is a slight book. Easy to read. So much of what you think is original in literature today can be traced to Unamuno and even Cervantes.

Sorry to lecture, but I love this stuff :))