Biochemical analysis on a very small scale is beneficial, and there are a variety of reasons for this: small samples lead to minimally invasive clinical/diagnostic procedures; multiple analytes can be measured from single traditional samples; most very small scale procedures lead to faster turn-around and present the possibility of massive parallel analysis; and less waste is generated. A less obvious aspect of small-volume chemical analysis on a fast time scale is that it will soon be possible to monitor biological processes on the same time scale and volume in which the intricate mechanisms of biochemistry occur in living systems. In fact, for microelectrodes, microdialysis, and near-field fiber-optic probes, this capability could be argued as a reality, albeit for a small subset of active biomolecules. This idea of intimately monitoring the chemical activity of living systems has essentially driven the field of ultrasmall volume bioanalysis, although it is unclear if the loose collection of techniques and methods that are utilized for these analyses even constitutes a defined field.