Theme：An aria, which is really a sarabande, which is really the first variation on a hidden theme (the bass line). Already very beautiful.

Var.1：A two-part invention which sometimes wants to be a swingy polonaise. Long phrases at first, then short.

Var.2：A triosonata that pretends to be a canon, at least for a while.

Var.3：Canon at the unison. Closely overlapping voices. Bach has to manipulate the bass quite a bit to make sure he reaches the V chord by m.8.

Var.4：Built around intense development of a single motif (often inverted). Bit like a passepied. (Also really fun to play.)

Var.5：Arabesque. Lots of hand-crossing. Theme especially clear in bass.

Canon at the 2nd. A neat perpetuum mobile of sorts, with an bias toward downward motion.

Var.7：Gigue. LH and RH closely related.

Var.8：A study in contrary motion, built from 1-bar phrases.

Var.9：Canon at the 3rd. The bass line starts to become obscure, and there are some gorgeous chromatic alterations (see e.g. the Neapolitan 6th m.11).

Var.10：A 4-part fugue, surprisingly assertive – the subject paraphrases the bass line really cleverly.

Var.11：More hand-crossing! You can really miss having two manuals here.

Var.12：Canon at the 4th. For the first time the answering voice is inverted. There’s something quite playful to this one：none of the phrases begins on the strong beat, and there are some fun chromatic touches (mm. 24, 26).

Var.13：The clearest variation on the original aria – but this is even more intimate and expressive. Lots of written-out ornaments. One of the most beautiful in the set.

Var.14：An all-out virtuoso showpiece. Yet more wild hand-crossing.

Var.15：Canon at the 5th. The first minor variation, with an inverted answer. Chromatically altered bass. Closes uncannily, over a huge open 5th.

Var.16：Opens with the biggest chord of the work thus far, a big bang of pure, uplifting sound. Celebratory, with lots of clever motivic manipulation (e.g., see how the closing bars steal the motif at m.18 to generate a sense of finality).

Var.17：Two-part invention, almost an etude. Shades of Beethoven’s 22nd Sonata. Gould affectionately calls it “a bit empty-headed”.

Var.18：Canon at the 6th. A particularly close canon, with the answer coming after just half a bar. A twin to Var.22. Chromatic modifications to bass at mm.14, 30. A happy thing. Tharaud's voicing at the repeats is particularly nice.

Var.19：Succinct. Extremely efficient motivic manipulation：the semiquavers at m.1 (and their inversion at m.3) generate the texture for the whole piece.

Var.20：Virtuoso, but also funny, with those opening syncopations and the triplet line rocketing up the keyboard.

Var.21：Canon at the 7th. A tight coil of despair, with lamenting chromatic descents in the bass. The counterpoint is stunning, especially in the second half. Miraculously, the bass theme remains fairly intact, and even manages to stay (if your ear can isolate it) in the major.

Var.22：Densely imitative, in a deliberately antique style.

Var.23：Yet another pretend-canon, opening with a rather coy tail-chaser. Recklessly funny, with a sort of silly virtuoso neediness to it.

Var.24：Canon at the octave. Sounds fairly mild-mannered, but everything about its construction is ferociously (obnoxiously?) ingenious. First the leading voice is answered one octave below (mm.1+3), then one octave above (mm.9+11). This means that the upper voice at mm.7-8 does not strictly need canonic treatment, but Bach reintroduces it anyway at mm.15-16 and 31-32. The voices switch roles at midpoint.

Var.25：Grief. Weighed with enharmonic colour (chromatic fourths + lots of lamenting motifs), and modulating to some fairly remote keys (Eb min), even as the basic bass progression is preserved.

Var.26：Pleasantly babbling. The LH actually plays out a tender sarabande which is all but buried under the RH exuberance.

Var.27：Canon at the 9th. A sign that things are coming to a head – for the first time there is no bass line.

Var.28：Trills as inner pedal points, invertible quavers. Paired with the next variation.

Var.29：Huge, joyous sonority, organ-like, the trills of the previous variation now broadening into thick chords. Coming after, running semiquavers that all but trip over one another in their eagerness.

Var.30：No canon! Instead a quodlibet (Compilation) of popular tunes. Because of this, this variation is often described as festive or funny, but this is an almost hilariously bad representation of how this variation sounds in context – to me it seems especially moving and luminous, even consoling.

Aria da capo. Coming home.