Ancestral Books, LLC specializes in rare and out of print family genealogy and history books. They have softbound and hardbound books available on every title and have been serving the community for over 10 years and you can visit them at www.ancestralbooks.comHere is an example of the kind of books they carry that can help you in your research:
Be warned that they have an F rating with the Better Business Bureau, and are infamous at rootsweb for spamming the boards there. Legacy told them to remove their affiliate banner from the ancestralbooks site due to the spamming at rootsweb. (and of course, he hasn't removed it)
I don't know why he says "they," either; it's his company.