What do you want to know specifically? The Wikipedia article on Dirlwanger is actually very well cited and researched. Since you've read that there isn't a whole lot more than can really be said about Dirlwanger's life. Unfortunately the only two in depth books I've come across about Dirlewanger are written by Rolf Michaelis and Will Berthold, two right wing extremist, Nazi apologists and thus I take everything they write with a grain of salt.

His name was Oskar Paul Dirlewanger - sorry for nitpicking.

Most of germans who served in his unit were petty criminals - specifically, poachers. Local collaborators were recruited too and at some point they constituted more than half of the brigade. Mostly they were picked by visual inspection - local polizai unit was mustered and Dirlewanger himself would inspect and point out his picks. Then they were warned, that they must obey or shot on spot. Some collaborators went over to partisans - including several german communists, who volunteered to the unit, thinking it would be easier to desert from there. Most of russian, ukranian and byelorussian collaborators was hunted down and prosecuted. Last massive process was in 1961. After that, only a small number of cases was prosecuted.

I could recommend recently published book -

(russian)Kovtun I, Zhukov D. - Hunters for Partisans. Dirlewanger brigade = Жуков Д., Ковтун И. Охотники за партизанами. Бригада Дирлевангера. Link to interview with authors. Book covers mostly Eastern front. It extensively cites an interview with surviving serviceman from the unit, done by Michelson (serviceman remains incognito).