These lectures concern basic aspects of the theory 
of semigroups of endomorphisms of type $I$ factors 
that relate to causal dynamics, 
dilation theory, and the problem of classifying 
$E_0$-semigroups 
up to cocycle conjugacy.  
We give only a few proofs here; full details 
can be found in the author's upcoming monograph 
{\em Noncommutative Dynamics and $E$-semigroups\/}, 
to be published in the Springer series 
Monographs in Mathematics.