Middleton's forwarding is considered to be superlative, while his designs and tooling, though restrained, are always in good taste and are superbly executed. He is also considered to be one of the most skillful book restorers at work today.
Aside from being a gifted bookbinder, Middleton is recognized as an outstanding scholar in the field of bookbinding history, and is the author of a comprehensive work entitled A History of English Craft Bookbinding Technique , as well as The Restoration ot Leather Bindings . He is unique among historians of bookbindings because he writes with such a vast knowledge of technique, largely overlooked by others.