From Zappa Wiki Jawaka
Fritz Rau (March 9, 1930 in Pforzheim/Germany) is a German concert- and touringmanager. He organized ca. 6.000 concerts in his 50 years of business life.
Rau organised the infamous Mothers concert in Berlin, 1968, which ended in a riot. Zappa later immortalized this event in his composition Holiday In Berlin, Full Blown. Rau himself is mentioned in Shall We Take Ourselves Seriously?: "Fritz Rau says: "Asparagus should only be consumed by people with a large amount in an unmarked bank account!"
Although Zappa vowed that he would never return to Berlin again, Rau managed to change his mind.