This document provides an overview of the National Geographic FieldScope program. It introduces key concepts including GIS, citizen science, geo-reasoning, and FieldScope. FieldScope is described as a GIS- and web-based platform for exploring citizen science data. The document explains how FieldScope can be used to teach geographic decision making and systems thinking through examples of human systems, environmental systems, and human-environment interactions. Finally, it provides suggestions for how teachers can get their students involved in citizen science projects on FieldScope.