Thanks to a detailed sketch, we know that Mozart originally wrote his famous Clarinet Concerto, K. 622 for basset horn in G or A. It was only in the early editions dating from the 19th century that this work - considered as the Clarinet Concerto par excellence - became unproblematic to play an the A clarinet. However, source studies have revealed that this was made possible only at the price of considerable "un-Mozartian" alterations of the solo Part. Sabine Meyer, Wolfgang Meyer and Reiner Wehle, the members of the Trio di Clarone, haue eliminated some of these modifications in their new edition, restoring Mozart's original intentions. However, their critical revision in no way impedes the performability of the A-Major Concerto.