The research librarians at the Penn State business library were invaluable in helping me find rare and important sources as well as to validate student usage of the MakerBots.
Bill Yackabonis at Autodesk, David Saint John at Linamar, and the team at the Penn State CIMP lab (especially the intellectually generous Tim Simpson) made me aware of emerging developments.
Working with the MIT Press on my second book with them was a pleasure. The editorial team of Marie Lufkin Lee, Stephanie Cohen, and Michael Sims guided me though the milestones, and the Press found excellent anonymous readers to help me push the project into some important areas I had overlooked in the initial proposal.
Special thanks go to CIMP-3D, Frustum, GE, and Unfold for allowing me to use their artwork in the book.
I appreciate the help of all of these contributors but all errors and infelicities in the final product are on my shoulders, not theirs.