Cataloging items in a series can seem complicated, but this information should help make it easier. It will also improve search results so that patrons are able to find all items in a series and the order the books were written.

If you have been cataloging for a long time, forget the 440 MARC field! It is obsolete and replaced by the 490 field. 

The 490 field is the transcribed series statement from the item.
490 1_ $a The Harry Potter series ; $v bk. 2
490 1_ $a History mysteries ; $v 15
This is the  “series statement” BUT it is not indexed by Horizon. To find the item in a Series Keyword or Series Browse search there must be an 800 OR 830 field added to the record but NOT both.
The 800 tag is used when a series is written by the same author. 
800 1_ $a Rowling, J. K. $t Harry Potter series ; $v 2.
The 830 tags are used for series that are produced by more than one author or a corporate body.
830 _0 $a History mysteries ; $v 15.
NOTE: In the 830 field the 2nd indicator is for the number of non-filing characters. In this case it is “0” but make sure you change that if the series name starts with “a, an, the”.
Many of our Bib records still have the 440 field in them but we do need to be moving forward using the  correct 490 field for the series statement and the correct added series information in the 800 or 830 field. And of course slowly working to update the old information.