Intense automorphisms of groups

Let G be a finite group. A good strategy for understanding the structure of G is that of studying
its group of symmetries, Aut(G). Let Int(G) be the subgroup of Aut(G) consisting of those automorphisms (called 'intense') that send each subgroup of G to a conjugate. Intense
automorphisms arise naturally as solutions to a problem coming from Galois cohomology,
still they give rise to a greatly entertaining theory on its own.

We will discuss the case of groups of prime power order and we will see that, if G has
prime power order but Int(G) does not, then the structure of G is (surprisingly!) almost
completely determined by its nilpotency class.