Chemical engineers are known for their versatility, and chemical engineering is known for its wide range of applicability. That wide range was reflected in Volume 1 of the Annual Review of Chemical and Biomolecular Engineering; it is similarly reflected in Volume 2.

The versatility of chemical engineers is a happy combination of curiosity and the courage to tackle new frontiers. Like Volume 1, Volume 2 indicates this happy combination.

Historians of science have often pointed out that in any discipline, knowledge grows not at that discipline’s center but at its periphery, where it interfaces with other areas of knowledge. This view is evident in the history of chemical engineering, and it points to its likely future. Many of the reviews published here were selected to reflect the fruitful tradition in which chemical engineers learn to develop and apply concepts and tools from any field of knowledge that might be useful for devising new chemical processes and products.

The goal of the Annual Review of Chemical and Biomolecular Engineering is to provide in-depth reviews of topics that are of interest to contemporary and future chemical engineers. The 24 reviews given here concern topics ranging from antibodies for cancer to stem cells, hydrates, insulators, catalysis, and risk in research and development management. The editors thank all authors for their fine contributions.

The editors are particularly glad to include a prefatory chapter by Professor Roger Sargent (Imperial College, London). Professor Sargent’s pioneering work in the second half of the twentieth century established new methods for optimizing chemical plant and process design; these methods are now routinely used throughout the world.

Once again I would like to express my gratitude to the Editorial Committee for their essential assistance and especially to Ms. Linley Hall for her consistent, prompt, and conscientious service.

John Prausnitz, Editor. University of California, Berkeley