This product is excellent, I do leave it on for half an hour and then wash off and wash again as usual, am pleased with the result of lightening grey in hair, and it does not make me nervous that it may be too strong
This book feels like one for the "specialist" rather than the plain enthusiast-the instructions for the patterns are quite difficult to follow without sheer determination to achieve the desired result of some rather fantastic socks. For a specialist I would rate the book as 5 star but for buying online it needed more explanation of what to expect. I have yet to complete the first of my pair of socks.... these are serious projects rather than quick results for cold feet. Yet I do think it is a worth while purchase.