http://Listen to An Oblique Approach by Eric Flint, David Drake on Audible. https://www.audible.com/pd/ [login to see] ?source_code=ASSOR [login to see] 0V
An extremely good series of books admittedly fiction but contains some very valuable real-world lessons. And also a fair amount of fairly accurate at least as far as I can tell historical information. Just a dang good read.