The work consists of two fugues (orricercari), II canons and asonata for flute, violin, ‘cello and clavichord.With the exception of the sonata and one perpetualcanon, the music of the original is not scored, andlooks rather theoretical and forbidding to the musiclover not initiated into the secrets ofcounterpoint. Bach indicates the form of the canonsonly by giving their principal line and the entriesand number of the voices; they must first be workedout before they can be read or played, andtechnically they are often extremely subtle. In oneinstance two voices move simultaneously in oppositedirections; in another one voice announces avariation of the theme, a second a differentvariation, which is also played by a third, but athalf the speed (per augmentationem)and in the exact inversion (per contrariomotu); or the canon strangely modulatesat the end of each repeat and passes step by stepthrough the keys of the tonal system, risingad infinitum, like Jacob'sladder. And over one canon Bach simply wrote “Seekand ye shall find,” without even telling us thenumber of voices! … I myself have found no fewerthan four solutions: two equally satisfactory andcorrect, and two rather modern in style.