I love a good "shelf brag", so if I've missed a book and you have one to suggest, please post your suggestion in the comments.
1) The Canadian Writer's Market (as recent as you can get your hands on)
If you're a freelancer in Canada, this book is absolutely critical to your success. It's a comprehensive lexicon of open (or close to open) writing markets in every single market you can think of and then some. Magazines, book publishers, newspapers... even Canadian blogs. If it pays and is a legitimate market, it's probably in there. They rarely miss a market and if they have it either isn't in business anymore, or is brand new on the market.
2) The Canadian Oxford Dictionary
I mean, you could use another dictionary. It would be accurate... But you live in Canada and there are nuances and other unique characteristics that make up Canadian English. You are a Canadian writer, right?
3) Prose Models (Canadian)
This is a textbook from university (I think - I actually found it while scrounging in the non-fiction section of a local used bookstore so I actually have no idea) but I highly suggest it to anyone interested in writing, in particular fiction and prose writing. As the saying goes, it's better to know the rules before you break them. This book will take you, in depth, into what makes good prose so you can take those rules to your own prose... and know when and where you can break those rules to create your own style. Once you know this, it's far more likely that a publisher will look at your manuscript and, possibly, even accept it. You could get the Prose Models text that covers the US, the British, and the Canadian prose in one text, and probably should if you can even find it. However, the Canadian one covers our great authors in better detail. You'll get more out of it than the other. After you finish with the Canadian Prose Models, by all means go find the other Prose Models. You'll be a better writer for it.
No, you can't have mine. I'm not finished with it yet.
4) The Canadian Press Style Guide
If you're going to write for the Canadian market, you need to know what the style is. This book will be your "go to" and should not be overlooked.
5) The First Five Pages
If you write novels, or even short stories, this book is critical. It's an in depth look on what it will take to hook a reader, and a publisher, into buying your book. In the case of hooking a reader enough for them to buy your book, that means royalties in your pocket. In the case of getting a publisher to move your manuscript from the slush pile to the "accepted" pile, that means actually getting your book published so that those readers can actually find and buy your book.
It's also useful for bloggers, essayists, and even non-fiction writers of both textbooks and shorter articles. Your income depends on getting people to read what you wrote.
This book will help you do that.
Did I miss one? Add your suggestions below!