- A “front list” book is new, expected to sell well and receives a lot of promotional effort.
- A “back list” book was probably published years ago. Sales are not so dismal that the book goes out-of-print, but it receives little or no promotional effort.
- A “midlist” book, as you might assume, is between front and back. Most books are midlist. Midlist and backlist books are important in publishing because they bring in money year after year with little or no effort or expense. Some writers are referred to as “midlist authors.”
(From my 1001 Powerful Pieces of Author Advice