Frank Zappa on Steve Allen's show, 1963.

It is an exceedingly strange overlapping of cultural eras, and big thanks to DW for pointing to it.

As in so many other cultural spheres, YouTube boasts a treasure trove of material pertaining to Frank Zappa's varied and all too short career in music. I recommend taking time to watch some of the videos available there, especially those dealing with Zappa's eclectic musical influences. There was little room for improvisation in Zappa's output; almost all of it was scripted and written in advance, and as such, he surely must be regarded as one of the great American composers.