  We study forking, Lascar strong types, Keisler measures and definable groups,
under an assumption of $NIP$ (not the independence property), continuing
aspects of math.LO/0607442. Among key results are: (i) if $p = tp(b/A)$ does
not fork over $A$ then the Lascar strong type of $b$ over $A$ coincides with
the compact strong type of $b$ over $A$ and any global nonforking extension of
$p$ is Borel definable over $bdd(A)$ (ii) analogous statements for Keisler
measures and definable groups, including the fact that $G^{000} = G^{00}$ for
$G$ definably amenable, (iii) definitions, characterizations and properties of
"generically stable" types and groups (iv) uniqueness of translation invariant
Keisler measures on groups with finitely satisfiable generics (vi) A proof of
the compact domination conjecture for definably compact commutative groups in
$o$-minimal expansions of real closed fields.
