Book excerpt: The continued improvement and reduction in costs associated with fiber optic technology associated with fiber sensors permit application areas that were previously inaccessible. These trends are expected to continue as new techniques become available and older ones are successfully adapted to new applications. This Field Guide provides a broad introduction to a variety of fiber optic sensors that have been successfully developed from the 1970s to the present. A wide range of examples are provided to inspire readers with ideas for new sensors and uses.