Of Some 150 Letterpress Printers, Publishers, And Print Dealers Active In Rome During The Long Sixteenth Century, Only A Dozen Ventured Into The Production Of Music Books. They Occupied Various Strata Of The Book Trade. The Largest And Most Important Mercatori Or Merchant-entrepreneurs Were Involved In The Publication Of Only A Relatively Small Number Of Music Titles. The Average-size Presses That Counted Music As One Of Their Specialties Issued The Bulk Of The Editions. At The Bottom, The Individual Tipografi Or Printers Did Not Have A Financial Stake In The Marketing Of Music Books, But Instead Worked On An Ad Hoc Basis For Other Bookmen. The Mercatori Dealt With Many If Not All Facets Of The Business. As Manufacturers Of Consumer Goods, They Directed A Complex Operation That Required The Investment Of Enormous Sums Of Money. They Formed Societa? Or Syndicates With Other Printers, Publishers, And Entrepreneurs. They Underwrote Publications Printed By Other Bookmen And Distributed Them Over An Extensive International Network. They Also Ran Their Own Print Shops And Often Held Interests In Retail Bookstores. Other Bookmen Took On One Or More Of These Roles. The Editori Or Publishers Financed Editions. Stampatori Or Printers Did The Presswork, And The Librari Or Booksellers Ran The Retail Bookshops-- Provided By Publisher.