Chris Shiflett's article this month is the "Article of the Month" on PHP Maagzine. It covers how to avoid the "Page has Expired" messages. These are the pages that aren't in the browsers cache anymore because the data it was passing back and forth has timed out. Thus there is a warning when the user tries to go back in the site, resulting in the familiar prompt.
You can check out his latest edition of the "Guru Speak" in this month's sample article - "How To Avoid Page Has Expired Warnings"...
