Craig Preston's book _How to Read Classical Tibetan_ (Snow Lion, 2003) examines a short passage (about 30 long lines in all) of the tract "The Great Treatise (or exposition) of the Stages of the Path" (Lam-rim Chen-mo) by the 14th century teacher Tsongkhapa (Btsong-kha-pa), founder of the Gelugpa (Dge-lugs-pa) school of Tibetan Buddhism.
In the course of the introduction and ten chapters the author goes through the long and short titles of the tract and then the 30-line passage, breaking the text into phrases and analyzing them grammatically from word to sentence level. He does this by means of well laid out labeled diagrams in which phrase-level structure is represented by boxes containing the parts of the phrases, which may be simple strings of text or nested boxes of the same type.
He includes a full glossary of the words in the text at the end of the book, and repeats the items occurring in each phrase in the section on the phrase, obviating the need to be constantly flipping between the phrase and the glossary. As far as I could tell he does not customize or enhance the vocabulary items for the individual phrases but copies them verbatim from the glossary, including the different roots of the verbs and the variants of the mutable particles (kyi, tu and so on) each time.
He intentionally focuses on the grammatical structure and literal meaning of the text and does not get into philosophical issues, though he does include, at the end of each chapter, with translations though not analyses or special notes, extracts from a commentary on the section of text in the chapter.
As a total beginner myself I cannot evaluate the accuracy of the book, but it appears to be carefully edited, and the grammatical analyses and translations all seem reasonable to me. He uses the Tibetan alphabet throughout and rarely if ever includes any transliterations. I think this is appropriate. The Tibetan alphabet is easy to master and anyone studying the language should learn it at the very outset.
He also, following Joe Wilson in his _Translating Buddhism from Tibetan_ (Snow Lion, 1992), uses opaque and confusing terminology for the cases (1st case, 2nd case and so on). This terminology derives ultimately from the Sanskrit grammarians and refers to the Sanskrit cases (1st case = nominative 2nd case = accusative 3rd case = instrumental 4th case = dative 5th case = ablative 6th case = genitive 7th case = locative), and does not really fit Tibetan. I would have been happier if he had used the simpler and more descriptive system of Nicolas Tournadre, _Manual of Standard Tibetan_ (Snow Lion, 2003) - a very good book BTW, with an extremely clear and thorough explanation of modern pronunciation (standard Lhasa dialect) - or even avoided the notion of case altogether and simply dealt in terms of the various particles (kyi, kyis, la/r/du etc.) as is done for Japanese (ga, wa, o, no etc.).
The work is clearly aimed at beginners. I would guess that a motivated student could work through the whole book at a chapter at a sitting and be done with it in a couple weeks. I can see it being useful for someone in the early stages of studying Tibetan on their own who wants to read some real Classical Tibetan with a good amount of hand-holding. The only prerequisite I can see, apart from the ability to read the Tibetan alphabet, is a level of comfort with basic grammatical concepts and the activity of detailed word-by-word phrase-by-phrase grammatical analysis.