The past few decades have witnessed significant changes in the nature of the data collected and analyzed as part of structural geology and tectonics research. Increasingly, geologists supplement and in some cases supplant sample and/or outcrop derived data on structures and fabrics (data focused on analyzing the movements of particles that occurred in the past) with data on the positions and movements of particles collected using global positioning systems, laser range finders, or other means (data focused on analyzing the current movements of particles). This change in emphasis motivates us to change the way we teach about displacements, displacement fields, and strains, material at the foundation of structural geology and tectonics. In particular, we find it reasonable (1) to provide students a comprehensive introduction to the measurement and analysis of the displacements of particles, (2) to analyze the characteristics of displacement fields, and (3) to draw upon that background to support analyses of strains and strain fields. This approach readily supports students with little experience with vectors or tensors by providing them with tangible examples of abstract concepts, enables the instructor to incorporate GPS data and geodetic data into demonstrations, exercises, or laboratories, and helps students to correlate more effectively their hand sample or outcrop observations to past or present tectonic movements. In this short course, we will outline one way to organize a displacement-then-strain approach and discuss examples of the benefits of such an approach. One of the most common and persistent confusions about structural geology in the general Earth Science community remains the distinction between stress and strain, which may even confound practitioners of tectonics. In parallel with the new approach to displacements and strains, we also propose a systematic approach to learning about stress, emphasizing tensor aspects, that will clarify the differences between displacements/strains which can be observed, measured or calculated directly from field data, and stress, which always requires an additional level of inference and/or assumption. This will lead to recommendations for a vocabulary to describe the fundamentals of deformation.