I think this grammar has good goals but needed more editing. Some things, like the ablative case, which varies in usage across languages, were not explained. Additionally, the verb tenses were given equivalents to tenses you'd expect to see in Indo-European languages, like past perfect, past imperfect, etc. However, when translated, these tenses don't actually match up to their past perfect, etc. equivalents. So it's very confusing why the author couldn't have just explained what the tenses are without giving them false equivalents.
The romanization of Mongolian is very idiosyncratic. Apparently this is to make the grammar easier for native speakers, however this doesn't make sense as so much of the grammar is difficult to understand even if you have a linguistics degree. Additionally, the author has a habit of throwing in historical forms of the language, which would usually be omitted in a grammar, slapdash in the middle of paragraphs. I don't think it's wrong to include this historical info, but the lack of clear separation between synchronous and dyssynchronous information means it's almost impossible to tell which is which. Thus, despite reading the phonological section many times, I still have no idea what the current vowel inventory of Mongolian is. I think this is a pretty big failure for a grammar that is supposed to be more focused on phonology than syntax and morphology. Also, the focus on phonology sometimes comes at completely inappropriate times. For example, when looking at noun cases, rather than explaining what the cases are and how they are used, the author gives a lengthy explanation of the phonology of the case endings and how they varies . This is just crazy, I've never seen it in a grammar before. It almost never explains what the cases are and how they are used, so if you're looking for an explanation of Mongolian syntax, I'd look elsewhere.
Finally, the nail in the coffin for me on this grammar is the lack of example sentences . There are no example sentences in the book except in the clausal syntax section, so if you're looking at case endings and want to find an example sentence with the case endings, you have to go to the clausal syntax section and pray you can find some there. I was reading an electronic copy that made this extremely difficult and time consuming. These means that there is some inflectional and derivational morphology mentioned that NEVER ACTUALLY APPEARS IN THE GRAMMAR . Again, this is just crazy. I've never seen this in a grammar before. Additionally, the author frequently makes claims about the language without providing supporting evidence, which is very obnoxious.
The only explanation for all of this is that it was edited by someone who had no experience with linguistics and/or had never read a grammar before. I was using this for a school project but had to switch to something else because I had already used most of the example sentences in the grammar and couldn't find examples of some things I needed. One of the most annoying things about this grammar is that there is no one place with all the morphological glosses, so I frequently had to completely guess what I was looking at. Again, never seen this in a grammar before. It's especially bad because Mongolian is a synthetic language so there are a lot of case ending. Unless you really need very granular detail on Mongolian phonology and are willing to read something 12 times, I'd avoid this grammar.