The Crazy Dell Numbering System
Dell 1437 Dell 8055
4568 (1975) 7650 (1973)
Candlelight 178 Candlelight 118
Listed with the "H's" Listed with the "S's"
The numbers on Dell books were pretty straightforward for the first two or three decades. They were in printing sequence (with the exception of a few reprints that added a "one thousand" digit). But then, after the "lettered series" (Dell First Edition, A-, B-, D-, etc), they switched to a "four digit" series ... and entered into a system that is unique in the literary world.
I'm being too kind ... it was absolutely bizarre!
Dell set aside "blocks" of 4-digit numbers, and then assigned a designation based on the first letter of the title. And so, for example, book numbers starting with "00" have a title that begins with the letter "A," but they are not necessarily in alphabetical order after the first letter. Starting with "04," the titles begin with the letter "B;" and those starting with "10," begin with "C." Sort of. You will notice in the "transition areas," there is some flopping back and forth (between "C" and "D," for instance, around the "1600" mark). With the book numbers between 2200 and 2800, the titles begin with both "E" and "F" indiscriminately.
And so, a book with a number in the "9000" range (that has a title beginning with the letter "W") might have been printed significantly before a book with a number in the "1200's" (that has a title beginning with the letter "C").
In the BookScans DELL database, if you note books within certain series, such as the Dell Candlelight series, their "series numbers" will be completely out of sequence. The sequence WAS in printing order for the series (for example, Candlelight #219 followed Candlelight #218), but NOTHING is in printing order within the 4-digit numbers. They are only listed according to the first letters of their titles.
(There are also some "exceptions." A few of the titles are obviously WAY out of alphabetical order.)
(Many thanks to Vintage Paperback expert Lynn Munroe for attempting to explain this to me.)