John James Wild, born Jean-Jacques Wild, was an artist and linguist. He was a member of the scientific crew of the historic Challenger Expedition (1863-1876), employed as the artist of the expedition, and secretary to the Expedition Director, Charles Wyville Thomson. During the expedition, two preliminary reports of progress and findings, containing illustrations of protists by Wild, were sent to the Royal Society in London and published in the Proceedings of the Royal Society in 1874 and 1876. Wild's figures of protists in the preliminary report of 1874 were the first illustrations of new organisms published in the scientific press. The figures of protists, and those of the second preliminary report, and an article in Nature, both in 1876, were very widely reproduced at the time, and over the years until present times, in both the scientific and popular press. Some of the figures of protists are now iconic. However, the artist who created them remains obscure as his name appeared rarely in the figure legends or plate inscriptions. Here the story of Wild is told, and his remarkable figures of protists, drawn while on board the Challenger, are shown. Some attention is given to revealing the use of his artwork by a variety of writers, including notable protistologists.