Bolometers for infrared and millimeter waves, as reviewed by P. L. Richards, are thermal detectors that measure infrared and millimeter wave radiation by converting it into heat. They are used in various applications, including astronomical and laboratory measurements. The review discusses the principles of bolometer operation, including the response of the detector to incident radiation, the role of thermal conductance, and the noise characteristics of the device. It covers different types of bolometers, such as semiconductor, superconducting, and composite bolometers, and their respective components and performance. The review also addresses the challenges in bolometer design, such as thermal feedback, noise sources, and the trade-offs between sensitivity and speed. It highlights the importance of low-temperature operation for high sensitivity and the use of high-temperature superconductors in modern bolometers. The review discusses the noise sources in bolometers, including Johnson noise, thermal fluctuation noise, and 1/f noise, and their impact on detector performance. It also provides formulas for calculating the noise equivalent power (NEP) and the photon noise contribution to detector noise. The review concludes with the importance of optimizing bolometer design for specific applications and the ongoing development of new technologies to improve performance.Bolometers for infrared and millimeter waves, as reviewed by P. L. Richards, are thermal detectors that measure infrared and millimeter wave radiation by converting it into heat. They are used in various applications, including astronomical and laboratory measurements. The review discusses the principles of bolometer operation, including the response of the detector to incident radiation, the role of thermal conductance, and the noise characteristics of the device. It covers different types of bolometers, such as semiconductor, superconducting, and composite bolometers, and their respective components and performance. The review also addresses the challenges in bolometer design, such as thermal feedback, noise sources, and the trade-offs between sensitivity and speed. It highlights the importance of low-temperature operation for high sensitivity and the use of high-temperature superconductors in modern bolometers. The review discusses the noise sources in bolometers, including Johnson noise, thermal fluctuation noise, and 1/f noise, and their impact on detector performance. It also provides formulas for calculating the noise equivalent power (NEP) and the photon noise contribution to detector noise. The review concludes with the importance of optimizing bolometer design for specific applications and the ongoing development of new technologies to improve performance.