(I already posted this in /r/History, but it didn't get much love there; also hoping I'm not going out of topic with this)
One of the classes I'm attending focuses on the military revolution between the XVI and the XVIII century, and how the shift from mercenary armies to standing armies happened. If we want, we're also allowed to write a short thesis (around thirty pages or so) about any argument we wish, as long as they're related to what we spoke of, obviously. Now since we only spoke marginally about Sweden - we shortly mentioned Gustavus Adolphus and its role in the Thirty Year War, but that was about it - I'd like to examine that a little more in depth. But of course, I need something to work on - in English, if possible; I know there's a lot of Swedish books on the subject, but I don't speak that language :p
Now, I already did some quick research, found out about the work of Michael Roberts and discovered some local libraries here have his books, so I'm definitely going to check those out. But if someone here knows about other good books on the subject, I'm open to advice. The more the merrier!
The books by Peter Englund are great, but unfortunately from a look at Amazon the only book available in English seems to be the one on Poltava. Not a bad start, but more narrow in focus than his other works. There are a few other of his books that are available in German if that is of any help.
I don't know much about their infantry, but i know a little about their navy in this time period. Since nobody has responded to this yet, i thought i might share the little info i have.
They were at war with Poland and some of the other countries in the Baltic sea. So they needed to invest in their navy, since there were almost no thread from an infantry attack. Their king invested in a lot of new ships in this time period, one of the more famous being the Vasa ship. This is a good example of military evolution, being sped up and causing more harm than good. Basically the king said to the engineers " Guys we need this ship to have three decks, i don't care that it is build for two. All the other kings are getting three decks on their warships. Make it happen". The ship sank shortly after leaving harbor. It was like their crown jewel at the time. It is very interesting, there are a lot of details and i would recommend you reading about it.
http://www.stockholmmuseum.com/information/general-info/vasa-royal-warship-museum-in-stockholm156.htm
http://faculty.up.edu/lulay/failure/vasacasestudy.pdf
Hope it helps a little.