Scholars are making extensive use of new digital technologies to express their research. Publishers, in turn, are working to support increasingly complex publications that are not easily represented in print. Examples include publications with embedded visualizations, multimedia, data, complex interactive features, maps, annotations, or that depend on third-party platforms or APIs, such as YouTube or Google Maps. These publications present formidable challenges for long-term preservation. To study this challenge, a group of digital preservation institutions, libraries, and university presses worked together on an Andrew W. Mellon funded project, Enhancing Services to Preserve New Forms of Scholarship, led by New York University Libraries. Publishing organizations included NYU Press, Michigan Publishing, the University of Minnesota Press, UBC Press and Stanford University Press. Preservation service organizations included CLOCKSS, Portico and the libraries of the University of Michigan and NYU. Together, they examined a variety of enhanced ebooks and identified which features can be preserved at scale using tools currently available. Their findings, combined with the knowledge and research of experts in preservation, publishing, and copyright, resulted in a set of guidelines and best practices. An interactive web version of the guidelines is published at https://preservingnewforms.dlib.nyu.edu.