Both biological examples and analyses based on molecular physics indicate that productive molecular machine systems can enable economical, large-scale fabrication of products built with atomic precision. However, a daunting implementation gap separates the nanostructures of today from the complex productive nanosystems of the future. How can this gap be narrowed and eventually closed? The development of adequate tools to build these systems will require several intermediate stages, each building on the results of the previous stage. Biopolymers (DNA, protein) can provide a basis for the design and fabrication of atomically-precise, self-assembling composite structures—they can form molecular components that bind and organize diverse nanostructures (nanotubes, macromolecules) to form molecular machine systems. This engineering capability will enable the design and fabrication of an initial generation of productive nanosystems. These in turn can be used to build non-biomolecular self-assembling structures, including a more advanced generation of productive nanosystems. Further steps can lead from the production of 1-dimensional polymers to 2- and 3-dimensional covalent structures, from self-assembly to simpler, mechanical construction methods, and from microscopic systems to desktop-scale factories. A roadmap under development will describe strategic objectives for current research and their relationship to long-term goals for advanced nanotechnology.