Humans and animals share a universal and intimate relationship that stretches from the earliest appearance of our lineage, through our prehistory, and into history and the modern era. Consequently, zooarchaeology -- the analysis of animal remains from archaeological sites -- transcends all cultural, temporal, and geographic boundaries, and therefore can be used to address questions spanning the breadth of archaeology. Over the past decades, the field has grown tremendously, from a small group of specialized practitioners to a large sub-discipline that is integrated with the larger field's research directions. Zooarchaeological analyses have addressed questions ranging from forager ecology to the processes of domestication to how animals function in the social realm. In each instance, methodological developments have been crucial in allowing existing questions to be tackled and new questions to be posed. One of the largest changes in zooarchaeology is a shift from considering how the environment has shaped human societies to considering how humans have altered the environment, a process that began deep in our prehistory. Applied zooarchaeology looks towards using zooarchaeological data to address questions relevant to conservation biology, two fields that are becoming increasingly integrated. Standardization of data collection and presentation, open access to these data, and global access remain challenges for the future.