Being in Canada, I have had the same response when I try to purchase from Amazon.com (USA), I believe it is just items that are not shipped out of the US, If available, I have to buy on Amazon.ca .
Max.
Some items come through Amazon, some come direct from the supplier and it depends on their individual policy.
In the case of books, I would recommend checking AbeBooks clearing house first, I have had some deals that put Amazon in the shade.
Max.
I tried all three. All returned "Sorry, this item can't be sent to your selected address. Learn more. You may either change the delivery address or delete the item from your order. You can also see if this item is available for delivery to your address from another seller."
Right now I'm trying with a local dealer who's like "let me look into my inventory" but you know... books like these are pretty low in demand.
Is it not possible to buy this book in Johor Bahru?
Are there no good bookshops that keep it in stock, or can order it for you?
Failing that, what about Singapore just "next door" over the causeway. You can buy all sorts of stuff there.