This baroque dance business never ceases to mystify me. Who the heck was doing all that dancing?? Take the cello suites or the partitas. Who on earth would "swing" -or whatever baroque move equivalent- to the bourrees, gigues or courantes. or waltz to the sarabandes?? I mean I have read the standard texts about the "origins" of these so-called dances but it just seems so strange that someone like Bach, a composer to the glory of God, would be so obsessed with composing dances right and left. It is not like he was a dancemaster to a glamorous court. Even when employed by Princes and Counts, it was in modest courts and in the seventeenth century in dreary puritanical Germany. And he did spend a lot of his life as a Cantor or music director in churches etc.. So what's up with all the dance business? Do we know if any of his Suites were ever used as real dance pieces (they must have had a weird sense of rythm, our Baroque ancestors. How did they choreograph the various voices??) I used to get "the look" from my teachers right around here. And perhaps there is a major gap in my reading about the subject. But though I am exaggerating a bit, I really don't get the "dance" bit beyond standard music history pronouncements. There, my ignorance is now documented to internet posterity.

Dance formed the basis of much of the music, providing different rhythms and tempi, as well as, therefore, different moods. Same applies to Chopin: the waltzes and the mazurkas, both 3/4, but differently accented.
No-one suggests dancing to Chopin (do they?), but the same principle applies.

No mystery to it. Composers build on what is already there. Geniuses like Bach transcend the original material, but the bases remain, like the difference between the running Italian Corrente and the swaying French Courante.

Both my wife and I play baroque music professionally, none of us knows any dances, we're to busy practising and playing the music.

That said.

I do belive it's of utmost importance that musicians learn to dance, or rather; shake their booty.
Any old way, any style.

And to the OP question; read about the period of the composer, what was going on at the time, both on a personal level (biographies, letters, etc), compositionally (theory, structure, etc) and socially (politics, movements, etc).

Yes, that is the generic or basic explanation. Nobody suggests dancing to Chopin, but neither do they suggest studying the "original" Viennese waltzes in order to understand Chopin's valses. For Bach, there is a greater emphasis on the need to study the Baroque dances (which? by whom?). It is no secret that studying the tempo and rythm of any piece is relevant to understanding its mood and how to perform it. But it seems to me that there is a greater emphasis on learning about the various "dances" that are supposed to have inspired Bach, though such material is not commonly available. Nor do I see how reading about the origins of the gigue or the bourree actually informs its performance, beyond knowing that the latter is often, but not always, in double time for example. I did look into some of these dances once. Some survive, in name at least, in various parts of Europe. They are all very local/ regional when they exist and quite different across countries. You would not, in your wildest dreams, inform your Bach playing by these dances. The knowledge makes you more learned it seems to me, but is not obviously connected to how we are taught to perform Bach.

I think we are at one with this: I have spent a lifetime playing Bach on piano, organ, harpsichord, clavichord without studying the dance forms on which Bach based so much of his music. But I hope I do feel the different pulse of each type. Certainly my body dances internally if not externally when playing the suites and partitas, with the LH providing the beat. Many of Bach's instrumental works are in trio sonata form, the LH providing the continuo, ie beat or pulse.
Bach, together with his contemporaries, seems to me to express feelings through rhythm in a way that his successors did not until the coming of Beethoven. A view which I suspect will not stand up to academic scrutiny.

I always think it is important to look at the connection between these three composers. There is the obvious connection that Haydn taught Beethoven. But you can get a great look into all their music when looking into these connections deeper. Beethoven takes some of mozart's melodies, and uses the compositional style of Haydn. Esp. in his early works. The more I listen to haydn, the more little quirks I also find in Beethoven. Upon looking in mozart more, I see his influence over everyone. I mean, it is a broad approach, but it can sometimes provide other insights.

I think the dancing insight with Bach is actually pretty good, and now that I think about it, I could make the case with that variation too.

I guess the only works of Bach with no dancing component are some of the choral pieces (e.g. chorales), and some of the very slow fugues (e.g. C# minor Book I, or D# minor Book II). Some of the more religious stuff, I suppose.

-J