The duets progress in difficulty, with parts being equal. Duet 1 is primarily half notes in 1st position, a few moving quarter notes. By Duet No. 7 eighth notes are incorporated, mixing of pizzicato with arco, and some double stops. By the end of the book there are dotted rhythms, some syncopation, always in the 1st position. Written in score form, both parts on the same page.