This thesis introduces digital materials by analogy with digital computation and digital communications. Traditional fabrication techniques include pick-and-place, roll-to-roll, molding, patterning and more. Current research in fabrication includes algorithmic assembly [3], programmed assembly[9], self-assembly[1,2], assembly by folding [4] as well as guided self-assembly [2]. While these research areas are studying means of fabrication, here we introduce the study of the digital materials they assemble. Moreover we present a new type of three-dimensional digital printer for use with functional digital materials. Most importantly, the digital materials are shown to be tuneable; the code describing a digital material allows one to predict and adjust the properties of the material itself. In the same 'way digital communications and computation are discrete in the code space, digital fabrication is discrete in the physical space. Just as digital communications enabled cheap long-distance communications and digital computation enabled cheap,universal and efficient computers, digital fabrication enables cheap, efficient and universal fabrication. Building digitally will reduce the complexity of the assembler and can produce a wider variety of objects for a smaller cost.