I can only agree with the previous reviewers. This modestly priced guide is also an outstanding work and a spin off from the excellent 'Field Guide to Moths...' by the same authors.
There are over 20,000 species of insect in the UK and over 2000 are moths. Not surprisingly, many books cover only selected species (and try to conceal this shortcoming) leaving one wondering if they are going to give a reliable identification. This book gets as close as one can to covering all the bases, as it has all the 'macro' moths (about 900 species, generally 1cm-2cm long and upwards).
The images are so much clearer in this book than those I remember from years ago (e.g. Richard South's two volume 'Moths of the British Isles'). These are hand drawn and coloured, which is superior to photography, where lighting can make species look different between the eye and the camera. Moreover, they mostly show the moths in their resting pose, as one would find them in the field, rather than in 'display case mode'; killed then spreadeagled with a pin stuck through them.
My only criticism is trivial. One assumes that most illustrations are meant to be life size , and the occasional image is marked as magnified, but this is not made awfully clear in the book. The necessarily terse text entries do give forewing length; well that's what I think it means because the abbreviation 'FW' is not explained either, as far as I can tell.
For good measure, the publishers have finished this book with a waterproof cover and wire ring binding. It is nice to see such care going into a useful book. There's absolutely nothing to match it for the price (or several times the price for that matter). Even if you don't want to go out moth spotting just leafing through the beautiful illustrations is joy enough.