  We prove for any pure three-quantum-bit state the existence of local bases
which allow to build a set of five orthogonal product states in terms of which
the state can be written in a unique form. This leads to a canonical form which
generalizes the two-quantum-bit Schmidt decomposition. It is uniquely
characterized by the five entanglement parameters. It leads to a complete
classification of the three-quantum-bit states. It shows that the right outcome
of an adequate local measurement always erases all entanglement between the
other two parties.
