Year-Round Gardening?

The idea of growing fresh vegetables year-round in my garden is fascinating to me.  I don't know how it would work, exactly, but I just have a feeling that I should be able to grow something, if I could just figure out how to do it. 

To that end, I've added another book to my official winter reading list that seems like it would be helpful in puzzling out this mystery.

Written by someone who lives in the mountains of Utah, where it snows (a lot) and gets pretty cold, it details his use of hot beds and cold frames...things I've thought about doing, but haven't really implemented yet. Perhaps this book will inspire me to work out a plan for next winter's growing season.