Sometimes I find an advanced mathematics book that does not state the pre-requisites in the preface or introduction. Is it acceptable to ask about them here? Perhaps someone could take a look at the book on Google books or Amazon and suggest something.
I would say Yes to whether it is acceptable, in the sense that I will not vote to close it as off-topic, for the following reasons:
- The question is arguably about mathematics and its education.
- The question is precise and limited in scope.
- While people may have some minor differences in opinion, questions of this type is largely answerable with a more-or-less correct answer.
- Questions of this type seeks "expert knowledge".
- Questions of this type could be useful for others (other people looking to read the same text).
On the other hand, I do not guarantee such a question would be well-received. For books that have extensive reviews on Amazon or google, or for books whose publishers conveniently included such information on their website (but not in the book), I may down-vote the question because the asker did not do the basic homework.
Lastly, to ask about prerequisites is to ask for a person to have read the book and to have remember the details and to contemplate what is needed as a background, both technically and pedagogically, for approaching that book. This is not an easy question to answer.
An easier question to answer would be:
I am reading so-and-so's book such and such. In Chapter 3 I ran into an unfamiliar concept X. Can someone point me to in which subject X comes up and is taught and perhaps recommend a good book on that subject if my goal is to learn the theory discussed in such and such?
In other words, you don't always have to learn mathematics forwards. As a popular legend goes Hobbes learned geometry by reading Euclid backwards. A big chunk of self-learning is adapting to handle situations like this (don't click "next", click on the image).