Undiscovered reserves in prolific, mature basins and bypassed petroleum in developed fields are key targets for increasing reserves at minimal cost. Geochemical tools can dramatically improve discovery and development success by identifying and characterizing these targets in both conventional and unconventional systems. Course participants learn to interpret geochemical logs, map organic facies variations, identify petroleum systems using multivariate data, and predict vertical and lateral variations in oil quality and gas-to-oil ratios. The course teaches how to integrate geochemical, geological and engineering data to identify reservoir compartments, allocate commingled production, identify completion problems, and monitor flood progression. The course also explains how to optimize development by predicting vertical and lateral variations in API gravity and viscosity. Attendees learn interpretive guidelines to evaluate geochemical data. Interpretation pitfalls are illustrated using exercises. Sample collection techniques are discussed. No background in geochemistry is needed.