Unfortunately the printing of this book leaves much to be desired.
On the inside page at the end of the book should be a map of the whole sky showing all the Messier Objects which is meant to orient the reader towards the right part of the sky, to then be able to focus on the more detailed maps (which cover a much smaller part of the sky) in the body of the book. However, in contrast to the 1st Edition, this has been omitted, though it is referred to throughout the 2nd Edition book. You can , however, get an official pdf version of the missing map and print it out enlarged in two halves and attach to the front and back of the book or you can zoom in on the image with an iPad or PC etc. See the following link to the resources section where you will find the pdf map insert http://www.cambridge.org/gb/academic/subjects/astronomy/amateur-and-popular-astronomy/deep-sky-companions-messier-objects-2nd-edition?format=HB The original map in the 1st Edition was rather small and many users would perhaps have another map which they would use in preference to it in any case.
In addition the quality of the paper seems inferior to others in the same series.. Thinner and therefore a bit wrinkly or wavy (not with creases) in parts.The blacks are not deep black.
These matters are somewhat disappointing in a book costing around £30.
However if you want an up to date book on the Messier objects with really good and interesting info from a first class observer- then this book may be for you.The smaller finder maps for each object are improved over the previous edition.
If you already have the 1st Edition then it might be a difficult decision to make- but if you haven't got it and are prepared to use another whole sky map or to download the pdf map and you don't want to wait for the publishers to correct their sloppy work with a 3rd edition, then this is a good buy overall.
Printing quality- rather poor and unprofessional- disappointing Overall content of the book- vg. Informative, interesting and up to date. Hence 4 stars