Hm... an OK but not great intro to Devanagari.
One of the aspects that I find annoying is the lack of IPA, which is by no means unique to this book. So far, I haven't found any intro to Hindi - or detailed reference grammars, for that matter - that consistently use IPA to make the phonetic values of the characters extremely clear. Instead it's the "like the 'o' in 'office'" style, which only works if all English speakers have the same vowel in the example word (but we don't).
If it interests you, there's a lot of introductory material on the sound inventory of Hindi and the history of words (which words are inherited, which are loanwords and if so, from which languages), etc. If you just want a basic intro to the script, though, you can safely skip that and go right to the chapters on the consonants and vowels.
My favorite part of this book is that the last section is a collection of handwritten Hindi to help you get acquainted with it, both to learn to write nicely yourself and to recognize other people's writing. More language books should include this!