As a professional artist I've found this book very useful for flesh tones. I'm an intuitive painter so don't used the plastic quantity guide in the back (why complicate the process?) Some of the oil colours aren't stocked by the 'big two' (Windsor&Newton and Rowney) in the UK as many have noted, but there are other manufacturers who do make them and who's paints are available through a number of online retailers. It's certainly made a difference to my work.
Please be aware that the description above is for the Epson V370 NOT the Epson V37. I bought this item with the intention of scanning old slides only to find that it didn't do what it said on the tin! I haven't used it, just packed up and returned so I can't vouch for how it works for normal scanning.