I would say that Telemann is one of the hardest to catalogue that I have ever seen. He does have a system: TWV numbers ranging from 1-55. Then, there is a sub-heading for the key and # in sequence. So, a sonata in g minor for Violin, Viola da Gamba & Continuo exists as TWV42:g10 (TWV 42 are all pieces for two intruments and continuo, the piece is in g minor and it is the 10th like it). It sounds complicated and it is. This problem is compounded with this fact as well: TWV42:g11 is also a sonata in g minor for Violin, Viola da Gamba and Continuo. So, unless you know Telemann's music extremely well (which I do not), I don't believe it would be possible to be 100% sure of what is on any given CD, and I feel that this is why labels leave the information off. Though this post seemingly makes little sense, there is, I believe, a good website that I have taken most of my information from. It is: http://infopuq.uquebec.ca/~uss1010/catal/telemann/telgp.html Sorry for how convoluted this post is. I have the system down in my head, but getting it on paper consistently proves to be difficult. Hope it helps for what it's worth. Daryl R. Loomis [log in to unmask]