Preface, flavoring and perfumery are very nearly the same practice. You can view the back catalog of the trade rag Perfumer and Flavorist, which will include formulae and articles of ingredients or industry developments. Of course there are books on the topic. The Good Scent Company is a free online database of aromachemicals. Further, you can buy these ingredients from places like Perfumer's Apprentice, if you wanted to get to know some of them.
For natural ingredients, you can usually just google the name of it plus "gcms" and get a list of known compounds in it with percentages.
Not an easy profession or hobby to get into, though.