This is a reprint of my original online article with the same title from Feb. 2007. I did not change anything except Markdown related formatting and a few typos. The original inline links are moved to a reference section. Some of them are dead links and marked (†). The reason for republishing is the announcement of JSONPath as an Official Internet Protocol Standard (RFC 9535) 17 years later based on that original article having a size of 6 print pages. I recommend to read Glyn Normington's blog post for some more insight to the spec and historical notes. This success would not have been possible without the professional editorial work of Glyn, Carsten, Tim and others. Thanks go to them.