There's a series of books by Ray Spangenburg and Diane Kit Moser called The History of Science. Actually, there are two -- one produced in the late 90s, and one produced in the mid-late 2000s. The second is just a shiner update of the first. Anyway, it's an excellent series for getting "caught up" in science, especially if you feel out-of-date. I read both series during two summer breaks from college to keep my scientific literacy polished. Should provide a basic refresher, from which you can look into more detailed books.
Other history-of-science books are good, too: Dan Falk's Universe on a T-Shirt is a popular read, while Theories for Everything is a more substantial volume.
I can't find History of Science, they all seem to be either out of print or nearly impossible to find. My local library doesn't have them either, and they tend to have the hard to find stuff. That said, "Universe" looks good, and "Theories" seems like it's right up my alley, and it looks like my library has both of them, so woohoo!, thanks!