Yes, thereon is not a word, but it got your attention, did it not?
On the copyright information page of most hardcover, and some paperback books there is a series of numbers, usually 1-10, arranged in various orders, e.g. 2 4 6 8 10 9 7 5 3 1.
Any ideas what these numbers mean?
H. Jacobson
Yes, the highest number showing is the number of the printing. This way, when the publisher orders a new printing they don’t have to make a completely new copyright page. Instead, they just block out the next number.
Ed Suranyi
Erm, that would be the lowest number showing. Otherwise the above answer is correct. Incidentally, if there are two different arrangements of numbers, the one with two digits indicates the year of publication. The practice dates back to hot-type printing, when it was much, much simpler to cut off the end of a line and recenter it than to reset an entire word or line.
Nowadays, of course, the practice is firmly entrenched, despite not being especially necessary. You’ve probably seen arrangements that would mot have worked back in Ye Olden Days, but are just peachy now. I’ve even seen one publisher of computer books that goes out of its way to provide a very compact edition/printing/year index, and then devotes an entire paragraph of text on their copyright page to explaining what it means, presumably so that both the printer and the reader can feel all special. But I digress…