  We review new aspects of integrable systems discovered recently in N=2
supersymmetric gauge theories and their topologically twisted versions. The
main topics are (i) an explicit construction of Whitham deformations of the
Seiberg-Witten curves for classical gauge groups, (ii) its application to
contact terms in the u-plane integral of topologically twisted theories, and
(iii) a connection between the tau functions and the blowup formula in
topologically twisted theories.
