Marc Riddell wrote:
I came across an Article in Wikipedia that needed categorization. The Article is a biography of a person in a field I am unfamiliar with.
Question: where do I go to get a list of all the Categories in Wikipedia?
Others have answered that specific question, but if you don't want to go rooting around trying to figure out the right category for an article on a topic you're not familiar with what you can do instead is just toss it into an overly-generic one such as [[Category:People]] or [[Category:Engineers]]. Eventually someone else will notice it and perhaps know of a more appropriate subcategory to shuffle it off into.
As a concrete example, I've been dumping articles on musical groups into [[Category:Musical groups]] for at least a year (whenever I stumble across one at random) and have never had any complaints. I also sometimes add a plain old {{stub}} tag and let the stub-sorters worry about the specifics.