In Series is a plugin that lets you write series of posts in WordPress, without having to deal with the hassle of manually writing up tables of contents or “next” and “previous” links in each post. It adds a new set of controls to the post editing screen, allowing you to add the post to a series (new or existing), re-order the post within a series it’s already in, or remove the post from a series entirely. In Series uses this information to automatically render all sorts of things — navigational <link> tags, tables of contents, previous- and next-in-series links, and more. The plugin also adds a new “Series” configuration sub-tab (under the “Options” tab in the admin pages), providing a highly-flexible mechanism for controlling how In Series renders content within your posts.
In Series requires WordPress 1.5.2 or later, including WordPress 2.3. There may be PHP or MySQL requirements as well — In Series is tested with PHP 5.2.4, and MySQL 5.0.44. It should work with PHP 4.3.0 and MySQL 4;