Physical technology evolves towards limits set by physical law, and a technology approaching the limits set by physical law must build with atomic precision. Molecular machinery provides a way to accomplish this.

In today's biological cells and in future manufacturing, large molecular structures can fit together and work together, forming molecular machine systems. These machines can bring molecular fragments together under digital control, building a wide range of products - large and small - with atomic precision. Biology shows that this kind of production process can be clean and inexpensive.

K Eric Drexler is author of Nanosystems: Molecular Machinery, Manufacturing and Computation (buy this book from Amazon (UK) or Amazon (USA)), and Engines of Creation: Nanotechnology - the Next Scientific Revolution (buy this book from Amazon (UK) or Amazon (USA)). See his website.