So I recently read a book called "Historical Linguistics" (3rd edition), by Winfred P. Lehmann, which talks about the way that languages tend to change over time, and the way that modern scholars investigate this change. There's a strong emphasis on methodology in this book, but there are enough historical examples from actual data that I felt like I learned some interesting historical content as well - particularly from the regions I'm currently interested in most, which are the various parts of Europe. (Although there is a significant amount of content from India as well.) I feel like I learned a lot from the book.
The textbook that I read