I would recommend The Dream of Reason by Anthony Gottleib, and his followup, The Dream of Enlightenment. And if that gets you interested, then the 5 volumes on

I would recommend The Dream of Reason by Anthony Gottleib, and his followup, The Dream of Enlightenment. And if that gets you interested, then the 5 volumes on the history of Western philosophy by W.T.Jones. As for Copelston, which some below recommend, it is too detailed for a beginner. And Russell has a strong classical analytic bias.