Ken Mallory is a registered member of the ABAA (Antiquarian Booksellers Association of America). Follow this link to see his member page at the ABAA website.

ABAA membership is an important marker of professional ethics:

"Membership in the ABAA cannot be obtained simply by paying a fee or signing an agreement. Before being considered for membership, booksellers must prove that they are established, knowledgeable, and of excellent reputation. Prospective members must be sponsored by current members, and undergo a rigorous screening process. The average ABAA member has been in the antiquarian book business more than twenty years."