  The paper considers (a) Representations of measure preserving transformations
(``rotations'') on Wiener space, and (b) The stochastic calculus of variations
induced by parameterized rotations $\{T_\theta w, 0 \le \theta \le \eps\}$:
``Directional derivatives'' $(dF(T_\theta w)/d \theta)_{\theta=0}$, ``vector
fields'' or ``tangent processes'' $(dT_\theta w /d\theta)_{\theta=0}$ and flows
of rotations.
