Looking at composer bibliographies it's evident that there are masses of way-out-of-copyright scores which don't see the light of day. Many of these are secrete

Looking at composer bibliographies it's evident that there are masses of way-out-of-copyright scores which don't see the light of day. Many of these are secreted away in libraries and collections. If you have use of such a resource, uploading some of these scores to online libraries like the Petrucci helps preserve the more recondite creative work of past generations for musicians and (hence) listeners world wide to enjoy. Most Petrucci users will have made their own discoveries of music they would likely never have encountered otherwise.