Where does "a work" end and "a collection" begin? A few hard cases I keep getting stuck on. I'm trying to organize my classical music library so the rotation engine I'm using doesn't keep playing me the same piece under different names. To do that I need a working definition of "one independent work" — what counts as a single thing, vs. a collection of separate things that happen to live together. My current working definition: > Easy cases: Bach French Suites are clearly six independent suites under one umbrella name (a bundle). Beethoven 9 is one work; Ode to Joy is an alias inside it. Vivaldi's *L'estro armonico* is twelve concertos. CPE Bach's Hamburg Symphonies are six. No tension. Where it breaks down for me: **1. Ballet vs. Suite.** Swan Lake exists as Op. 20 (the full ballet) and Op. 20a (the concert suite Tchaikovsky drew from it). Same for *Nutcracker*, same for Prokofiev's *Romeo & Juliet*. Are these two-member bundles (ballet + suite as siblings)?…