North American Maple Syrup Producers Manual, 2nd edition
A must have for any serious producer. One of the best books out there that cover all aspects of maple. This book has chapters on History of Maple Syrup and Sugar Production, Maple Resource, Planning an Operation, Managing Maple Trees, Sap Production, Syrup Production, Syrup Filtration, Marketing and many more. With over 300 pages this book is full of wisdom.
North American Maple Syrup Producers Manual (pdf) The maple manual is out of print. It is available instead as a for-sale PDF from Ohio State University Extension. Note that a more recent edition is available on this site here.