I bought this hoping for a complete course in the tongues of Middle-Earth. Upon receiving, I realised the subject was a lot less learnable than I hoped. But, the book does an excellent job of introducing the languages, and the committed reader will soon pick up the Elvish tongues at a basic-to-sort-of-advanced level. I have been reading it for 3 days now, and I already possess the knowledge to translate sentences of Quenya easily, albeit with dipping into the Lexicon occasionally for assistance with unencountered words.
HOWEVER, and this is a pretty big HOWEVER (hence my use of the rarely employed "caps lock" key of my keyboard), this is outdated. There are numerous inaccuracies, and I found myself browsing the interweb for assistance with the "reconstructed" pronouns of Quenya, which are mostly incorrect. Please consider that this IS NOT (more caps!) the blind ignorance of the rather excellent Authorship, as I have only the greatest respect for Jim Allan and his fellow students of the Eldarin tongues, but it is, in actuality, the result of outdated research. These words written in this book were before the release of "The Etymologies", and there are a few grammatical rules which have been proven wrong, as well as the extensive Proto-Eldarin section, which is only partly correct.
Nevertheless, I thoroughly recommend this for the beginning student of Tolkien's languages, but one with a little bit of previous knowledge of grammar and linguistics (perhaps a dip-in student of Latin or Greek). Read a quick guide to linguistics ("the Pocket Linguist", or "Aitchinson's Linguists - Teach Yourself" for the hardcore gangsta), there are quite a few on Amazin' Amazon, or browse the endless wonder that is the Interweb for some linguist guides, and I'm sure you'll feel comfy traversing the epic early research that is "An Introduction to Elvish". You'll be telling Quenya jokes in no time! And after a little bit longer, you'll be telling your friends to jump into an orcish cesspit in an extremely threatening tongue (yes it covers some bits of Black Speech! Yay!) After this book, you'll find yourself wanting to expand your vocabulary; I find myself googling for new bits of Quenya to translate this early on in the reading.
PS Use a highlighter; the book becomes so much easier!