Lepidopterists' Society FAQ
http://www.lepsoc.org/frequently_asked_questions.php
What's the difference between a moth and a butterfly? Why are moths attracted to light? This FAQ has the answers.

Louis Handfield, Le guide des papillons du Québec - Nouvelle edition, Broquet, 2011, ISBN 978-2-89654-245-1
This book is the most comprehensive resource for identifying butterflies and moths in the Ottawa area. The colour plates are excellent, and the species are listed by Hodges number. The colour plates in the new edition are even better than the ones in the first edition (1999). Invaluable. Don't worry if your french is rusty (or non-existent); it contains a short chapter in english explaining how to understand the most important data.

Charles Covell, A Field Guide to Moths of Eastern North America, 2nd edition, Virginia Museum of Natural History, 2005, ISBN 1884549217)
The second editor of the classic Peterson's Guide.

Lynn Scott's Lepidoptera Images
http://acleris.com/dls/mothhome.html
Lynn Scott has been photographing the moths that arrive at her front door (quite literally) of her home in Dunrobin, just west of Ottawa. Her web site has images of hundreds of moth species found in the Ottawa Valley. Several of my images are of moths that Lynn caught for me at her place.

Rick Cavasin's Butterflies of Ottawa-Gatineau
http://sites.google.com/site/ottawabutterflies/
Rick is a good friend and collaborator who takes great pictures of butterflies in the Ottawa area.

North American Moth Photographers Group
http://mothphotographersgroup.msstate.edu/MainMenu.shtml
Another great resource for identifying north american moths.

Joseph Scheer, Night Visions: The Secret Designs of Moths, Prestel Publishing, 2003, ISBN 3791329685
I collected butterflies and moths as a kid. My interest in local moths was rekindled by Joseph Scheer's Moths of Allegany County project, which was featured in the May 2002 issue of National Geographic Magazine. As well as exhibiting his prints worldwide, his project led to this wonderful book. I employ similar techniques to his.

David L. Wagner, Caterpillars of Eastern North America: A Guide to Identification and Natural History, Princeton University Press, 2005, ISBN 1884549217)
Lavishly illustrated with pictures of both the caterpillars and their moths.