What is a “trade paperback” and how does it differ from any other kind? I see this sometime and recently saw it compared to “mass market paperback” when looking at dictionaries to buy online. I assume it is a reference to the bookcover and not the content, although the contents may differ for other reasons.
A mass market paperback is 5" by 8". Trade paperbacks are larger, usually the same size or only slightly smaller than a hardcover version. The contents are the same.
Mass Market (MM) paperbacks use the cheapest quality paper (sometimes newsprint) and a very basic binding. They are not intended to last past a few readings. Generally, they cost less than $10.
Trade paperbacks (also known as Quality Paperbacks or QP) are like “mid-grade” between Economy MM and Premium hardcovers. They are intended to last on your shelf, though not as long as hardcovers of course.
Paper quality is almost always superior to MM. In size they may range from just a bit bigger than a MM, up to the size of a full-size hardcover.
In price, they are usually $12-$16.
The definition of “paperback” and “trade paperback” in the publishing industry has nothing to do with their size (though the previous definitions are generally correct). It has to do with their returnability.
Trade paperbacks are books that bookstores are required to return the entire book to get credit for the returns (books are sold on consignment – bookstores can return unsold hardcovers and trade paperbacks for full credit). They’re called “trade” paperbacks because you trade them back for credit.
Regular mass market paperbacks are not returned to the publisher. Unsold copies are stripped – the front cover (or ISBN code nowadays, which may be on the back cover) is returned to the publisher for credit, while the rest of the book is pulped (i.e., thrown away – they cannot legally be resold).
Trade paperbacks are a little more sturdy so that the publisher can ship them out and resell them (in theory, at least – a book’s shelf life these days is usually so short that there’s no long-term market). They are often the same size as a hardcover, but there are some that are standard paperback size.