Philosophical Letters
Or, Letters Regarding the English Nation
I’ve read a few of these so far, in particular the letter on smallpox inoculation, indicating that the practice was well-known in England by the time of this writing in the 1730s. Also interesting were chapters on Bacon, Locke, and Newton. (I learned from this that that the fact that light travels at a finite speed was first demonstrated in the 1600s—and the first estimate of its speed was only 26% lower than the modern value.)