Peter Tchaikovsky

Tchaikovsky wrote the most recognisable orchestral music of the nineteenth century and a great deal of piano and vocal music that almost nobody plays, and the catalogue reflects both — thousands of entries, most of them arrangements of the famous works for every conceivable combination.

The genuine piano repertoire worth knowing is The Seasons, twelve character pieces of moderate difficulty that are among the best intermediate Romantic writing there is, and the Album for the Young, which is exactly what it says. The First Piano Concerto is advanced and the arrangements of it are legion; check what you are buying, because "Tchaikovsky Piano Concerto" covers everything from the full two-piano score to an eight-bar simplification.

For the ballets, the same caution applies twice over. Swan Lake, The Nutcracker and The Sleeping Beauty exist as full scores, piano reductions, suites, and hundreds of arrangements at every grade. The listing rarely tells you which, so look at the page count.