I borrowed several canning books from the library in addition to the one I bought with my canning equipment.
I read the purchased book first, Ball Blue Book Guide to Preserving, where I learned that canning is not quite what I thought. That big black pot is only for some canning; I need a pressure cooker for a lot of it too. Huh.
Then I read Put 'em Up! This book is nicely arranged as a resource for any type of preserving and using produce. The step by step instructions for processes range from traditional canning to freezing and even making infused alcohols and vinegars. When I saw several pages for an "obscure" item like rhubarb, including how to freeze it, I knew this is likely to be a book I go buy. I did not learn kitchen skills growing up, so this could become a great resource.
I also read/skimmed Canning for a New Generation and Canning and Preserving. They both seem like useful books. I would consider picking up a used copy of either but Put 'Em Up was my favorite, then Canning for a New Generation and then Canning and Preserving.
Update: I decided to order Put 'em Up! on Amazon. I am a little baffled by why I would buy a used version. It appears cheaper but when you add shipping, it costs the same. Wha...?