The watercolours used are mainly Daniel Smith.
It's a helpful resource for artists who might want to try out new colours and see how they mix with the colours they already have.
The book's available in digital ebook on Blurb and Apple iTunes store. A physical copy is also sold on a print-on-demand basis but that's a bit pricey.
Check out the book and some preview pages at https://goo.gl/6uJAGV