The trend of miniaturizing (bio)chemical assays has been first seen in analytical and combinatorial chemistry and was soon also introduced in life sciences. The reduction of development and operating costs are the main motives specially in the biotechnology and pharmaceutical industry. In fundamental research the application of single- molecule techniques rather than bulk measurements allows the characterization of mechanism and transients states that would otherwise be hidden or diminished in measurements averaged over a whole population of molecules. This book covers the basics and concepts of single-molecule detection and specifically deals with the development and implementation of miniaturized biochemical assays. Tethered particle motion (TPM) and nanoarrays are discussed in detail, which have been applied in DNA and protein research. This book should be helpful for those how are interested in single-molecule detection and the miniaturization of biochemical assays.