  Euclidean supersymmetric theories are obtained from Minkowskian theories by
performing a reduction in the time direction. This procedure elucidates certain
mysterious features of Zumino's N=2 model in four dimensions, provides
manifestly hermitian Euclidean counterparts of all non-mimimal SYM theories,
and is also applicable to supergravity theories. We reanalyse the twists of the
4d N=2 and N=4 models from this point of view. Other applications include SYM
theories on special holonomy manifolds. In particular, we construct a twisted
SYM theory on Kaehler 3-folds and clarify the structure of SYM theory on
hyper-Kaehler 4-folds.
