I haven't quite finished the book yet, it's not quite the thriller like the books it was based on, that you simply can't put down before reading "just one more chapter." However, for those interested in such things, it is rather well written (the sort of thing I would expect from an expert in both the language the reader is familiar with and the one he/she is attempting to learn about). The primary motivation for the review though, is to respond to some of the previous reviewers, who make some rather harsh accusations concerning David Salo's supposed lack of "proper citation," among other things.
Certainly I am no linguist myself (in fact, if I were, I would probably do the research myself) and lack the expertise to comment on some of the more technical aspects of the work, but I am more or less literate, and I was able to comprehend the preface to the book which clearly states, "This volume is not and cannot be the last or most accurate word on Sindarin... within the limits of the available source material, I believe this work to be accurate in general and in most points of detail... where gaps occur, they have been filled in by educated guesswork marked as such". That being so, those of us who have no formal education in linguistics, may find it very difficult to pick out the subtle nuances that experts such as Tolkien used in their creations.
It is, therefore, immensely helpful for those of us with an interest in learning a particular language, to have someone who is trained in such things do the research for us and fill in gaps more accurately than we might have ourselves. At the end of the day, Tolkien did not publish an all-encompassing guide to his works, so any reasonable interpretation of the missing pieces can hardly be called "unreliable."
As far as the citation comment, Tolkien's name appears on the front cover above the author's in the same size and style of print. This is effectively a textbook. I imagine most people don't randomly find this book with no foreknowledge of Tolkien's works and think to themselves, "what a great idea, I'll study an imaginary language for no particular reason!" One probably starts by reading the Lord of the Rings and desiring to learn more, and when you've run out of works written by the creator himself, what's the next step? Beyond that, the first 18 pages are actually a short recap of much of the history written in The Silmarillion and the other histories published by Christopher Tolkien. In this section, one can hardly two sentences without running into a cited reference, book and page number included.
Perhaps there are other works on the subject that Mr. Salo could have attributed his inspirations to, but seriously, he spent enough time researching and writing about the subject. One can hardly expect him to attempt to go back in time and make a note of every last detail in his life that led to the completion of this work. I am annoyed by the mere mention of legal proceedings.
Please try to find a book written about person A by person B that person C can't criticize for reasons D, E, or F. Good luck.