The present transcription for three trumpets (or clarinets) has been transposed down a major third to facilitate performance on modern instruments. Performers should consider the following options in selecting instrumentation: 3 trumpets and trombone, 3 trumpets and keyboard accompaniment (with optional trombone), 3 clarinets and bassoon (or bass clarinet), 3 clarinets and keyboard accompaniment (with optional bassoon or bass clarinet). An appropriate bass instrument doubling the lowest keyboard line was a custom observed in Gabrieli's time. The present editor of this performance edition has provided dynamics, articulations, bar lines, ties, and the keyboard realization. Musica ficta has also been employed. It is hoped that "Sonata No. 21" will be accepted by brass and woodwind players as another fine example of Giovanni Gabrieli's beautiful style of composition. -the publisher