Development of Language Book

It's a shame this book is still usually considered the go-to introduction to the Etruscan language, considering that so much of it is'to put it kindly'complete amateur hour garbage.

A lot of this is certainly due to Bonfante senior, the linguist of the pair, who by 1983, when he was 79, had apparently been retired long enough to have forgotten many of the basics of the field as well as to have accumulated a lot of "idiosyncratic" views, especially when it comes to etymology. Some of the appearance of the former can perhaps be attributed to the fact that the book starts out wanting to be accessible to non-linguists (this presumably explains the claim that "[a]lphabets when they are first used are strictly phonetic"), though it does change its mind about that a few times, rendering particularly the phonology section fucking unreadable, as it avoids succinct jargon in favour of laborious circumlocution in heavy jargon. (It also changes it mind about whether or not it expects you to have any experience with Latin. Expect to enjoy "participle of obligation" rather than "gerundive", but also not to have cases explained to you.)
Most of what makes the book bad, however, has to be attributed to the fact that what we know about Etruscan grammar can fit on four pages, and the complete vocabulary on seven more (more if you want to separate early Etruscan from late, which you should but the book does not), but the Bonfantes seem to be loath to admit that and so obscure it with poor structure and copious filler. Some of that filler is more than fair enough (archaeological context, the Sources chapter that shows what actual text on actual artifacts looks like), some of it is embarrassing and/or irrelevant (e.g. the chapter on how Etruscans gave the Germans their runes'fundamentally true, but none of the details provided have any basis in material evidence; the claim that contact between Germany and Etruria is confirmed by the word Erz 'ore', which Bonfante repeatedly claims derives from the name of the city of Arrētium (Etruscan Aritim, though he lists it as Aret-(?)) is bunk), some of it is outright academic malpractice (the Glosses chapter, which lists "Etruscan" glosses by various Roman and Greek authors, a solid majority of which are transparently nonsense and most of the remainder of which need heavy footnotes, with translations but zero commentary). Very much not used to pad anything out is an explanation of how we know almost any of the things the book claims we know about the language, even when many of the claims are outrageous on the face of it: it's briefly mentioned why ś was probably [ʃ] "as sh in shin" (though not in the phonology section itself, obviously, which only suggests that s and ś might have been allophones of a single phoneme'uniquely in the alphabet, in fact, as though literally three paragraphs earlier it wasn't talking about c, k, and q), but if you're hoping for an explanation as to why liciniesi hirsunaieśi in mi liciniesi mulu hirsunaieśi 'I have been given by [allegedly] Licinie Hisunaie' is a dative of agent rather than a normal-ass dative you'll presumably have to go digging in the bibliography.
And the bibliography is extensive, though much of it is in Italian, which is also ostensibly the reason the Bonfantes wanted to write an introduction in English in the first place.

I do think every Latinist has a moral duty to have at least a survey-level awareness of Etruscan, but this book is an unpleasant and inadequate way to acquire it. Thankfully, there seem to be English-language alternatives now, and I'll be checking those out.