The CABI course will cover the fundamentals of nuclear, magnetic resonance (MR), optical, and optical-genetic imaging. For each modality a series of three lectures will develop the basic concepts of the imaging contrasts, a fourth lecture will address contrast agent performance, and a fifth lecture will review primary literature and tour experimental labs for developing agents. Lectures on nuclear imaging will cover the rich history of radiopharmaceutical development, concept of nuclear decay and different classes of radionuclides based on half-lives and energy spectrum. Lectures on magnetic resonance imaging will include an introduction to relaxivity principles in traditional and new contrast agents, designed to enhance efficacy. Breakthrough concepts such as hyperpolarized MR spectroscopy will be introduced. The first block of lectures on optical imaging will cover physical chemistry principles inherent to optical contrast with a focus on fluorescence and the fundamental design strategies of optical imaging agents and reporting strategies for cellular and sub-cellular activation of molecular probes. A second block on optical imaging will cover genetic strategies for neural circuit and discrete cell type and signaling imaging. Starting with an introduction to Cre-Lox recombinase technology followed by genetically encoded reporters of structure, such as green fluorescent protein and genetically encoded reports of function, such as calcium indicators (GECI). The course will close with advanced optical modulation strategies for active optical imaging, including super-resolution techniques and various optogenetic approaches. For each modality, a brief introduction to the hardware will be presented. Prereqs: one year of general chemistry, one semester of organic chemistry.