One of the things that has most interested me through the process of book gathering, collecting, and reading is the info and insight being provided by the various authors. They are "passing along" their knowledge about other writers; writers less well known - forgotten - out of print - but not gone. Definitely not gone. The mere mention of these forgotten souls triggers interest in readers like me to find out more about them.
Michael Dirda, the book reviewer for the Washington Post, for example, presented Dawn Powell, Alfred Bester, and others as though they were delicacies of a by-gone time.
The book collector and author Jack Matthews, a professor at Ohio University, wrote about Ralph Hodgson. Hodgson lived in Ohio at the end of his life and at the time of the publication of Matthew's Memoirs of a Bookman (1990) was scarcely recalled. Nowadays his many books of poetry and editorial work is in greater demand. One wonders if the essay in Matthew's book contributed to the revival in interest in Hodgson's body of work.
Thirdly, Paul Oliver who blogs at The Devil's Accountant provides the same level of discovery as the afore mentioned writers. Oliver dusts off lost classics as well as publishers who work needs greater attention.
Collectively they and many others help to "pass along" their expertise to the future. As it should be. As it needs to be.