This will be a short review:
If you need to learn more about Canadian wine (such as a WSET or Court of Master Sommeliers student) this is indespensible. For the average consumer, it is overkill.
Canada makes serious wines and this is a great view into the wines, regions, and producers that are putting Canada on the map for something other than the horrors that are Celine Dion, Alanis Morisette and Bryan Adams.
Pros: Great Depth, well written, nice producer bios
Cons: Maps (as always with Faber Faber books) get the Atlas of Wine.