After Katherine Bailey's excellent series of articles (see "The Lowdown on jQuery in Drupal":
http://jquery.com/). And articles such as Katherine's certainly illuminate any AHAH problems developers tend to encounter.
But, what is Ajax? And what is AHAH? How do you wrap your head around the whole Rich Internet Application framework question? Also, why did Drupal chose jQuery over other extremely serious contenders? And what can rich internet middleware do for an application like the On-Line Literary Workshop?