Some time ago I read Peter Englund's work on the 30 years war. In his book Englund focuses on the Swedish perspective on the war and the biography of Erik Dahlberg, a Swedish officier who later (after the 30YW, during the Deluge) rised to the rank of a marshal of the Swedish army. It was really an interesting change from the usual German perspective on the 17th century (usually limited on the religious clash and the decay of the HRE's central power).