TITLE: Wielandt automorphism tower theorem
QUESTION [5 upvotes]: I wanted to know if anyone can point me to an (ideally freely available) english translation of the proof of Wielandt's Automorphism Tower Theorem (1939).
The theorem states the following:
Given a finite, centerless group $G$, its automorphism tower terminates (stabilizes) in finitely many steps.

REPLY [4 votes]: The theorem appears as Theorem 9.10 in
Isaacs, I.Martin, Finite group theory. Graduate Studies in Mathematics 92. Providence, RI: American Mathematical Society (ISBN 978-0-8218-4344-4/hbk). xi, 350~p. (2008). DOI 10.1090/gsm/092. ZBL1169.20001, MR2426855.  
The proof given there is very detailed (and well written). (But I think this book is not freely available.)