The guide arose from a survey of UK users and manufacturers/developers to assess detector equipment usage and calibration, in order to identify the factors influencing the accuracy of measurements obtained with detector array equipment, and thus develop calibration techniques and establish best practice procedures. The text contains both a review of the existing literature and a large amount of new experimental data obtained during the course of the study. The main emphasis has been on UV, visible, and near-infrared systems that use silicon detector technology, but the issues arising in thermal imaging with infrared detector arrays have also been addressed, along with brief sections on EM CCDs for low-light-level imaging and on lag effects in CMOS active pixel sensors.