The field of molecular sciences is witnessing a revolution. From elementary reaction dynamics to protein folding, new physical tools are being exploited to study molecular structure and dynamics in chemistry and biology. The great strides made in both spatial and temporal resolution, down to the atomic scale, provide new opportunities to elucidate the nature of elementary processes in complex molecular systems and to relate dynamics and structures to function in real systems at the most fundamental level. To address the complexity of real systems, it is essential to draw upon different scientific sub-disciplines and to exploit synergies between them. The goal of the Laboratory for Molecular Sciences (LMS) is to conduct multidisciplinary research on fundamental processes in complex molecular systems with atomic resolution. Collaborations have been established to pursue this objective in a wide range of complex systems using experimental, theoretical, and computational approaches. These efforts draw upon the active participation of research groups from physics, chemistry, and biology. The Laboratory is equipped with state-of-the-art resources for ultrafast studies, including lasers, x-ray diffraction, electron diffraction, high-speed computing, and biochemistry. The activities encompass areas such as the development of 4-D time-resolved diffraction techniques for resolving structural changes in space and time; studies of nanometer-scale systems, clusters, and interfaces; and studies of electron transport in DNA, molecular recognition by proteins, and correlation of biological dynamics with function. Theoretical studies are an important part of the research at LMS. LMS was founded at Caltech in 1996. We are grateful to the National Science Foundation for their generous support, which, along with other resources, has made it possible to bring together scientists and students from around the world. We at LMS welcome new participation in the exciting research endeavors at the interface of chemistry, physics, and biological sciences, some of which are highlighted in the following pages. Ahmed Zewail