GURPS Steampunk 3: Soldiers and Scientistshttp://www.warehouse23.com/products/gurps-steampunk-3-soldiers-and-scientists
Which completes the starting set of GURPS 4th edition steampunk PDFs (along with 1 and 2 and Conveyances); to put it another way, put those four books together and you'd have approximately the book I'd have written if SJ Games had been willing to do a new-edition GURPS Steampunk.
This one is the characters book, which means a lot of templates, but I tried to add more interest with variant skills and disadvantages and martial arts styles and so on.
