Actually that isn't a book but an Amazon special offer. I have the K4 NT SO model. In this case, Amazon sent a link to an article on their CS website on how to create and use Collections. Normally we get special offers on discounts for purchases, but occasionally we just get a tip.

BTW, there is an eBook attached to the K4 NT Tips thread in the sticky area of this forum that lists all the Tips we have found so far.