Book excerpt: "Field Guide to Infrared Optics, Materials, and Radiometry covers all aspects of IR optics, including monochromatic and chromatic optical aberrations as well as important concepts such as depth of focus, depth of field, hyperfocal distance, warm shields, aspheric surfaces, and kinoforms. It also provides a comprehensive introduction to the optical, mechanical, and thermal properties of infrared materials as well as the essentials of radiometry and sources necessary for the quantitative understanding of infrared signatures and flux transfer, spectral atmospheric transmittance, and path radiance"--