Okay, first, just to clarify the "royalties" thing. I reiterate, this has nothing whatsoever to do with the GST collected by Amazon when someone buys a book.
If I was a computer programmer, and I did some work for a Canadian company, I would have to charge them GST on my bill, i.e. 6 hrs @ $75/hr = $450, + 5% GST = $472.50 ttl. If the company is non-Canadian, I don't have to do that.
My accountant thinks that the royalties that Amazon pays me (if they come from Amazon Canada) are the same 'kind' of income as a billing for work done, and therefore I should be charging Amazon GST on top of the royalties. OR, I have to remit 5/105 of my royalties to CRA if I want to just eat it.
It's looking less like Amazon is a Canadian entity, though, for purposes of this transaction. I had to fill out and sign a form when I set up my account with Amazon so that they wouldn't withhold tax at source. I think it was a W-something, and I'm in the process of searching for the URL to look at it (can anyone help with that?). Anyway, if my memory is correct, it's for the IRS, which would make the entity that I'm dealing with American by definition. If I can just find that form and take an image of it, it should settle things.