Codes are revised every couple of years. So there's always a new one in the making. When you buy your copy of the orange book, it'll say which revision of the CEC it corresponds to. If the orange book date _itself_ is less than 2-3 years old, you have the right one.
It's not so much accessibility of J-boxes (which is required of course),
with more than, er, 1M (~39") I think of headroom, because they're a snag hazard. There's other stuff about headroom, etc. Most of these rules are similar to the NEC, but the details are different.
The rules aren't onerous, and inspectors do give some leeway, the book will help him understand the simple rules he should follow about wire and box placement.
P.S. Knight's books are somewhat unique.
In both the US and Canada, there's an official national code (US: NEC, Canada: CSA CEC), and usually it's adopted and amended somewhat for each state (or province), and municipality.
Most of the "Wiring Simplified" books in the US and Canada are generalized books that don't get into fine detail, make no allowance for regional variation, and may be based on codes that are years out of date. In some cases, following these books to the letter will be wrong for your location, and to be 100% accurate you have to either have the real code on hand ($$$), or ask an inspector a lot of questions.
P.S. Knight, on the other hand, publishes what is defacto the official "electrician's training manual" for Canada, with different versions for each provincial code, and is updated in full synchronization with the code revisions. The DIY book I'm recommending is similar - each province has a different version, and it's updated in sync with the corresponding official code.
For a Canadian who is asking basic questions, you can _never_ be wrong recommending the PS Knight "Electrical Code Simplified" (ECS) book that they can obtain in most hardware/DIY stores in their province.
As the ECS obsoletes fast (every 3-5 years), it's produced cheaply, uses hand-drawn (kinda primitive ;-) diagrams and is quite inexpensive. It doesn't have fancy binding or extensive color photos of each motion needed to twist two wires together. It won't win any design awards.
It's a cheaply produced paperback book full of scribbles.
Until the last edition it looked _almost_ like it was done with a manual typewriter in bad need of readjustment, primitive charcoal cave drawings, and photocopied ;-) But it has always answered all the code questions, makes suggestions on (legal) short cuts and has other hints and tricks. Even a bit of humor. _Very_ well written for the beginner.
If the person needs basic skill or design handholding, they need one of the pretty books. [The Reader's Digest DIY book is my favorite]
You can also recommend the Electrical Wiring FAQ, noting the caveat that it is somewhat out of date.