This fugue on "Allein Gott in der Höh' sei Ehr'" is a concise but masterfully crafted contrapuntal work. It demonstrates Bach's ability to build complex textures from simple thematic material.
Developing a clear understanding of the contrapuntal lines and achieving good voicing are crucial for performance.
Allein Gott in der Höh sei Ehr (BWV 675) is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 6.
You should be comfortable at Henle level 4 — meaning you can already play level 3–4 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Allein Gott in der Höh sei Ehr (BWV 675) lasts about 3 minutes.
Allein Gott in der Höh sei Ehr (BWV 675) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.