I am not sure this is the right place to ask this question, but I want to learn the history of this part of Hitlers army. It's a bit of a jungle out there so any helpful books, articles and other kinds of reading material would be appreciated.
The SS was more than "just" a part of Hitler's army but an organization with a very varied and changing history. Aside being part of the armed forces trough the Waffen-SS, they also ran the Concentration Camp System, provided internal security in the party with the Sicherheitsdienst (SD), and most importantly probably merged with the police as part of what they called Staatsicherheitskorps (State security corps).
As varied as their functions is the literature that it is out there about the organization but generally I'd recommend the following:
Richard J. Evans Third Reich triology gives a very good general overview and does go into detail concerning the SS and its role in the Nazi State.
Heinz Höhne: The Order of the Death's Head: The Story of Hitler's SS. (1967) is older and in some parts outdated but still gives a good general overview of the history of the SS in general.
Ulrich Herbert's biography of Werner Best and Michael Wildt's book about the RSHA are excellent in terms of covering the merging of the SS with the police and its role in the Holocaust and the occupation of Europe. Wildt is almost certainly available in English, Herbert I don't know (I assume, you don't read German).
Biographies of Heinrich Himmler also usually cover a lot of ground. In English probably the best available are those of Richard Breitman and Peter Longerich.
I haven't read Weale, Adrian (2010). The SS: A New History yet but I heard good things about it and it is probably the best place to start off.
Another one I'd personally recommend is Gerald Reitlinger's The SS: Alibi of a nation.