Mapping the Republic of Letters is a cartographic tool designed by students and professors at Stanford that seeks to represent the Enlightenment era Republic of Letters, the network of correspondence between the finest thinkers of the day, such as Voltaire, Leibniz, Rousseau, Newton, Diderot, Linnaeus, Franklin and countless others. Patricia Cohen wrote an article about Mapping the Republic of Letters as well as other datamining digital humanities projects in The New York Times. The mapping tool is fun to play with but I recommend you read the blogpost where Cohen explains how to use Mapping the Republic of Letters.
Few books written in the 18th Century are better known or more read today than Candide, Voltaire's great satire of optimism. The New York Public Library's Candide exhibition has many delights, including Rockwell Kent's famous illustrations. Many other artists have illustrated Candide, and many of those images can be seen in the University Library of Trier's Candide image database. If your eyes are tired, you can also download an audiobook of Candide for free from LibriVox, or you can listen to a lecture on Candide [iTunes] by Stanford professor Martin Evans. Adam Gopnik explains how Candide fits in Voltaire's life and what it can teach us today. And don't miss this old post about Leonard Bernstein's Candide operetta.