If so, I would highly recommend "Radical Enlightenment: Philosophy and the Making of Modernity 1650-1750" by Jonathan Israel.

This book is a comprehensive history of the early enlightenment, with an emphasis on the point that there were both mainstream and radical wings of the movement, and that the foundations of the modern world are largely based on the ideas from the radical wing. It concentrates on the central position of Spinoza and his thinking, and gives lots of interesting background information on the underground community that distributed his ideas. Even stuff like detailed analysis of the contents of various private European libraries...