You also drive down wages for honest, hard-working online retailers, a group that includes a number of laid-off workers, single moms and the employees of any number of online retailers.
It’s like scabbing minimum-wage McDonald’s workers by telling the boss you’ll run the registers for free if he just pays the customers your wages.
There are rare cases where someone might be interested in an old textbook. Earlier this year I obtained from some Internet source (possibly abe.com) copies of the textbooks The Control of Language: A Critical Approach to Reading and Writing by Alec King and Martin Ketley, published in 1939, and The Reading and Writing of English by E. G. (Ernest Gordon) Biaggini, published in 1936. These are long out-of-print books by some Australian writers, although the books were published in the U.K., to teach English composition to high school seniors. They would be useless to anyone today except that C. S. Lewis quotes from them in his book The Abolition of Man. He refers to them by made-up names to avoid directly attacking them, but it’s clear from the quotations he gives which books he meant. He uses them as examples of the attitude he is criticizing in which it’s claimed that all moral values are merely relative. I wanted the old textbooks for research into the book The Abolition of Man.
Those are cases where it might be possible to sell the book online. Charity book sales generally despise old textbooks. Nobody wants to buy them. You’re hurting the charity by giving them the books, since they have to pay to have them hauled away after the sale.
It seems to me we are in complete agreement. I never said put the whole books, covers and all in the recycling. 
Post the titles in the Marketplace forum. I vaguely recall a few previous threads where people were giving away old textbooks and people actually wanted them.
Just for reference about the concept we’re all dancing around here, those textbooks are firmly in the trough of no value, where the cost of preserving them exceeds the value of having them. As Gary “Wombat” Robson says, though, this trough is of finite extent; antiques are items that have survived the trough and emerged out the other side with positive, and increasing, value. Further, some things never really enter the trough: Wendell Wagner mentioned some of them, and the reason why, and I’ll add that anything written by Knuth or another legend in a given field will never truly have zero value.
Help Anyone with Medical / Nursing text books that might be 3 - 5 years and have been gently used? Can arrange to have them shipped over to Zambia for a College of Nursing I am starting up!
I am starting up a Nursing College in Zambia, Southern part of Africa. One of the things required is a well-stocked Library. So if you or anyone else on this forum are still looking for a charity or institution that can take your Medical / Nursing text books, I would take them and even pay for shipping.