The best general all-around book on canoe maintenance, restoration, and building is "The Wood and Canvas Canoe: A Complete Guide to its History, Construction, Restoration, and Maintenance" by Rollin Thurlow and Jerry Stelmok. It is, unfortunately out of print, but you may be able to get it at your library, and used copies are often available on eBay or at Amazon or other used book dealers.
Proper care of a canoe that is in good shape is not really difficult -- keep it painted, renew the varnish when necessary, keep it dry when not in use, and store it off the ground. If you poke around these forums using the search function, you will find a good deal of information about painting, varnishing, and repairing dings and scratches.