  We study the coalescence of non-spinning binary black holes from near the
innermost stable circular orbit down to the final single rotating black hole.
We use a technique that combines the full numerical approach to solve Einstein
equations, applied in the truly non-linear regime, and linearized perturbation
theory around the final distorted single black hole at later times. We compute
the plunge waveforms which present a non negligible signal lasting for $t\sim
100M$ showing early non-linear ringing, and we obtain estimates for the total
gravitational energy and angular momentum radiated.
