Anthony Lockwood of Desktop Engineering writes a review of a white paper from ZCorp that explains in 2D print form the entire process of 3D printing for beginners.
While the PDF paper is somewhat (well, quite a lot actually) slanted towards ZCorp's line of 3D printers, it is very well written for those who are unfamiliar with the concept of 3D printing and want more than just a consumer view. Beautiful diagrams accompany the text to illustrate each step in the process, be they microscopic or office-sized.
The paper explains the beginnings of 3D printing at ZCorp, and then sails smoothly through each step in the process of producing a coffee cup. From design, printing and finishing, it's a great read.