José Ortega y Gasset was a Spanish liberal philosopher and essayist working during the first half of the 20th century while Spain oscillated between monarchy, republicanism and dictatorship. He was, along with Kant, Schopenhauer, and Nietzsche, a proponent of the idea of perspectivism.
About 2/3 of this is an immensely comprehensive, nearly pedantic, exploration of how Aristotle's thinking about logic was taken up and developed by the Scholastics, such that it was able to be developed into something new by Descartes and Leibniz. These sections, particularly in the middle, were very dense, so I skipped a good amount of it, honestly.
The other 1/3 is an assessment of philosophy's situation by the first half of the 20th century, and this I found the most interesting and valuable. He discusses his dissatisfaction with Heidegger and "existentialism," in addition to justifying the task of philosophy as a discipline.
The first appendix, on Leibnizian optimism, was quite fascinating too, with what he says about ontology.