In an earlier post, I described how I found that Bristol City Library had filed Becoming Drusilla under 306.768 (Culture & Institutions: Sexual Relations: Transgenderism and Intersexuality). Further research showed that Jan Morris' autobiography Conundrum had been placed in the personality disorders section, where it was sandwiched between a couple of books about child sex offenders and their victims.
I sent a copy of my previous post to Bristol Central Library, and got a reply yesterday.
Dear Dru Marland,
Your recent e-mail querying the classification of books on transsexuality/transgenderism, has been passed on to me as I am responsible for classification and cataloguing at Bristol Libraries.
The basic answer to your question is that we classify any book by its subject matter, regardless of whether the author has written books on other subjects or is more famous in another field.
So - 306.768 is the number for transsexuality, and as the book "Becoming Drusilla" is about the biographee's change of sex, this is the correct number. If any other material on her was published we would classify it according to what it was about - not necessarily 306.768
Similarly, Jan Morris' s "Conundrum" is about her change of sex, so 306.768 is the correct number for it. The more recent edition of the book is at this number.(the older (1974) version is, as you say at the medical number 616.8583, which is now incorrect and unacceptable, and I shall alter this). Other books by Jan Morris are classified in their individual subjects - travel, architecture, history, etc
With regard to your Noel Coward example, 822 (plays), 792 (stage presentation), 821 (poetry) are examples of the different numbers used. If a book specifically about his homosexuality was produced then it would be classed at the relevant number (306.7662)
I hope that this clarifies the situation for you.
So, a small step forward. But more work still to be done. Watch this space. Or not, of course, as you please. I do think that, in its small way, this stuff is important, because the way we categorise things is indicative of the way we think about them. We have come a fair distance from 1974, when Conundrum could so readily have been categorised as it was, in a way that is now recognised (if only when it has been pointed out) as unacceptable. But the journey isn't over yet.