  We present a new method for quantum process tomography. The method enables us
to efficiently estimate, with fixed precision, any of the parameters
characterizing a quantum channel. It is selective since one can choose to
estimate the value of any specific set of matrix elements of the super-operator
describing the channel. Also, we show how to efficiently estimate all the
average survival probabilities associated with the channel (i.e., all the
diagonal elements of its $\chi$--matrix.
