The first person to ever use the word Ajax to refer to the package of technologies that comprise the transferring of XML and other data to and from web servers via HTTP was Jesse James Garrett. Garrett first used the term in February 2005 in an article he wrote for his company, Adaptive Path, titled ‘Ajax: A New Approach to Web Applications.’
In this article, he references CSS, XHTML, DOM, XSLT, XML, XmlHttpRequest and JavaScript as the technologies that define Ajax. Needless to say, this is an incomparable piece in the history of the Internet. That, coupled with the fact that his name is ‘Jesse James’, makes Mr. Garrett the man.