Chemistry is typically described in introductory texts as the study of the properties and behavior of matter. A more modern definition might take the microscopic view and describe chemistry as the science of atoms, molecules, and their interactions. As such, chemistry crosses scales from isolated, individual atoms and molecules to complex interacting collections of molecules such as those found in the cell, and disciplines from biology and medicine to materials science and engineering. This broad range of applicability is why chemistry is often referred to as the central science. The field has traditionally been divided into sub-disciplines including analytical, biological, inorganic, organic, physical and theoretical chemistry, but the increasingly interdisciplinary nature of chemistry makes such categorizations limiting (although they largely persist within the undergraduate chemistry curriculum). Indeed some would describe chemistry in terms of what chemists do, for example designing and synthesizing new molecules and materials, developing new experimental methods and instrumentation to probe, characterize and manipulate molecules, and developing new theories and computational methods to understand and predict molecular behavior. Current interdisciplinary applications of chemistry at Duke range from elucidating and controlling signaling in biological systems, to designing chemical separation and identification technologies for genomics and proteomics, to developing new chemical contrast agents and imaging methods in biomedicine, to the synthesis, assembly, and theory of nanoscale materials and devices. Training in the discipline must then go beyond the traditional areas of chemistry and provide sufficiently general skills and a sufficiently broad understanding of molecular science that the power of chemical thinking can be brought to bear on complex scientific and technological problems for the betterment of society. The A.B. degree program allows greater flexibility than the B. S. program in scheduling and course selection, while still maintaining the integrity of the Chemistry major. Students with interests in a second under-graduate major or in advanced work in a professional school (e.g. medical, dental, veterinary, business, or law) following graduation should consider this program. Students with an interest in employment in the chemical or a related industry, or in advanced study in chemistry or a related science (e.g. Biochemistry or Pharmacology) may also consider this program, although they are encouraged to augment their program with additional upper-level chemistry courses. Students in this category should consult their faculty advisers early in their junior year.