This special issue on novel interferometry results from a suggestion by John DeVelis, over a year ago, that we attempt to find a number of papers on novel interferometers. This sounded intriguing, but what is a "novel interferometer"? Novelty implies uniqueness, which in turn leads to finding new interferometers that are somehow different from the commonplace interferometers widely used today. Of course, we would have to search out not one, but many "novel interferometers" to fill this special issue. Seeing this as a formidable task, we decided to broaden the scope of this special issue to include: unique applications of interferometry, truly novel interferometric instrumentation, and the integration of interferometry with other technologies. Thus we could pursue developments which incorporate new technology to the now familiar interferometers developed through the years, as well as informing the reader of new applications of interferometry in other disciplines. In keeping with the purpose of Optical Engineering, our intent was to seek papers stressing instrumentation and application as opposed to purely analytical treatments.