This workshop emphasizes newest developments in understanding geochemical and biogeochemical reactions and processes controlling iron cycling and bioavailability in the environment, from the atomic scale to the field scale. Factors driving iron cycling are multifaceted and their study necessitates an interdisciplinary discussion among chemists, microbiologists, hydrologists, geologists, and mineralogists. This workshop is the next of a regular biennial series on this topic that has facilitated such discussion with great success. The workshop intent is to share current findings, stimulate new ideas, and generate collaborations among leading researchers to help advance new ideas