Talk pages are generally for discussion of the page they're associated with, rather than the subject of the page they're associated with, except to the extent that the subject has to be discussed in order to converse about what content should go in the page. E.g., a Book talk: page should generally be devoted to critiquing the content on that page only for purposes of revising the book. If it's a book that won't be revised — as would be the case with, say, Book:Human Action, since the author, being dead, won't be making any further revisions, and it is appropriate for those who disagree with that book to write their own work rather than publishing a book to which they have made unauthorized revisions under Mises' name — then the Book talk: page would be an appropriate place to talk about, e.g., disputes about what text should be considered authoritative (e.g. the first, second, third, or fourth edition).
Essayspace or reviewspace would be more appropriate places for discussion of the subject of a page, if there is no intention to work toward revision of the page with which the talk page is associated.