Reading western philosophy is a life-long project (that one can complete generally by about age 40 with a lot of reading. Start with Plato’s books where he narrates the dialogues and conversations of Socrates. Then proceed up along an historical timeline all the way to the 21st century. There are numerous books summarizing Western philosophy such as those by Will and Ariel Durant, Betrand Russell and Frederick Copleston.. Read primary books by famous western philosophers and learn for yourself what ideas they developed, and how those ideas built upon one another’s ideas constructively;each philosopher had a place in history. Some such as Socrates, Kant, Hegel and Hume, Berkeley, J.S. Mill and Jeremy Betham are essential reading. One may read people like Schopenhauer and Nitzsche for more depth, and eventually move into the Vienna circle era and with those associated with it developing formal logic. Sartre was a novel expositor of French rationalism continuing in the tradition of Rene’ Descartes. Aristotle , Liebnitz and Frege developed logic.
Linguistic philosophy is based on logic and the structure of words and meaning, and that is great stuff and useful in numerous areas today with such obvious applications as in computational logic. The twentieth century was something of a renaissance for philosophy with epistemogical inquires using formal logic, inward and outward meanings of words and objects shedding light. Classical ideas about nominalism and pluralism, knower and known and so forth were informed with ideas from modern physics and logic.
William James and John Dewey continued practical applications of philosophy. America had people like R.W. Emerson and C.S. Pierce yet Saul Kripke, P.F. Strawson and W.V.O. Quine wrote informatively about the mind/language/external reality interface with logical analysis. Eventually while reading philosophy one should read a few of the works by great historians such as Arnold Toynbee (A Study of History) and then read in a third thread the major works of Eastern philosophers (Nakamura’s ‘Ways of Thinking of Eastern People’ is good) such as Confucius, Lao Tzu, Sakyamuni Buddha, and histories of the founders of the major and minor religions such as Mani and Manichaeanism, Zoroaster and Muhammad.
One would do well to keep a King James version of the Bible around and read that forever, here and there as the spirit moves one. There are innumerable stops on the way of reading history and philosophy together, such as the history and life of St. Augustine, neo-Platonism such as Plotinus (with the Enneads), Stoics like Marcus Aurelius and Empedocles and so forth. There are even pre-Socratic philosophers with great ideas; for example, Parmenides and Heraclitus. It is necessary to learn a scientific history of cosmology and quantum mechanics as well. Philosophy does exist in a real Universe with quite a bit to consider.