I'd love to see most advertising simply banned, but in the case of books there's precedent from back when people used to actually read enough to be worth advertising to: mid-century pulp novels often had a couple pages of glossy ads right in the middle, usually including one or more cigarette ads.

The first or last pages of books are still frequently used to sell other books from the same author or from the same publisher. Not that long ago they'd come with cut-out cards to mail in for your order for more of the publisher's books from the partial catalog printed in your book (nobody orders by mail any more, is the only reason the stopped that, I assume). Some of my books when I was a kid would have the first chapter of another book from the same anthology series at the end, to sell it (Goosebumps did this, for example).