Are academic book buyers legitimate? I have recently been receiving number of visits from "academic book buyers" that are looking to buy books that I no longer want.  It is never stated outright but they seem to be looking mainly for evaluation copies of textbooks.  At least 2 of the cards that I have been given indicate that they are "recycling" the books, although what this means is not clear.

Are these book buyers benefitting or exploiting academia?
I agree with Yves that they are selling the books back to students.  Then I think the economics works out as follows:

The faculty selling the books and the book buyers benefit a lot.  The publishers stand to lose some money, since reselling the books hurts the market for new ones.  They presumably pass some or all of this cost on to students through price increases, so the students also lose money in aggregate.  Now the question becomes what price the books are being resold at.  If they are resold cheaply (used book prices), then the students who buy the resold books benefit (they get near-new copies at cheap prices), at the expense of the other students.  If the books are resold at new prices, then no students benefit.