Harvard Art Museum uses the abilities of the Web to present this collection of seventeen rarely seen paintings by Piet Mondrian, known as the "transatlantic paintings," begun between 1935 and 1940 in Europe and completed or altered after Mondrian arrived in New York City in 1940. The nine pages of introduction explain the techniques that curators at Harvard used to study the revisions that Mondrian made to the paintings, including studying archival photographs and examining the transatlantic paintings with stereomicroscopy, X-rays, ultraviolet, and infrared light. The Studies and Details sections provide in-depth examinations of eight paintings, and all seventeen can be viewed in the Gallery section. Selecting a particular image from the interactive "gallery guide" requires a plug-in, but users can view all of the paintings without it. The lengthy background section entitled Career covers Mondrian's life and work, illustrated with more of his paintings and photographs. There is also a specialized glossary for the site, complete with definitions of technical art terms (impasto, raking light, inpainting) and biographical information on Mondrian's contemporaries who are mentioned in the background essay.