This refers to Bach's compositions originally intended for the lute, likely transcriptions or adaptations of his keyboard works or pieces written specifically for the instrument. These pieces showcase Bach's ingenious ability to adapt his contrapuntal mastery and melodic invention to the unique timbral qualities of the lute.
Requires delicate touch and awareness of string resonance for authentic lute-like phrasing.
Bach-Kompositionen für die Laute is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7.
You should be comfortable at Henle level 5 — meaning you can already play level 4–5 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
Bach-Kompositionen für die Laute is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.