Book excerpt: Directed assembly of single molecules is a central theme in nanotechnology. This body of work was inspired by a specific challenge involving ordered deposition of single DNAs on surfaces for massively parallel single molecule DNA sequencing via fluorescence microscopy. A potential 10-fold gain in data density is possible if single molecules can be forced into a regular array rather than randomly deposited. The dimensions of such an array are difficult to achieve with conventional lithography techniques. On one end, molecules must be separated by sufficient distance so their optical signatures do not overlap. This distance is on the order of hundreds of nanometers. On the other end, the attachment points for the molecules must have molecular dimensions. Bridging these two length scales is a formidable task. The ability to place nanometer scale objects with nanometer precision can been achieved through atomic force microscopy, scanning tunneling microscopy, optical tweezers, and ebeam lithography. All of these techniques, however, are serial in nature and hence do not serve the intended gain in data density. Another approach toward directed patterning of single molecules is through self-assembly. In this work, self-assembly of block copolymers is explored as a means to addressing the molecular and optical resolution length scales simultaneously. First, the challenge of molecular patterning for single molecule fluorescence microscopy is explored theoretically and the limits of this approach are defined. Block copolymers are introduced as a possible solution to generating the correct surface patterns for improved data density, and experimental results are compared to theoretical predictions. Second, the surface chemistry of these arrays is characterized, and I will show they can be selectively functionalized in preparation for directed assembly of DNAs. Third, these arrays are integrated into single molecule fluorescence imaging experiments to determine their potential for improved data density. What emerges from this work is not only a viable platform for increased single molecule fluorescence data density, but also a deeper understanding of the requirements for directed self-assembly of single molecules.