Recent advancements in reconfigurableElectromagnetic absorbersAbsorber, especially Active FrequencyFrequency Selective SurfacesFrequency selective surface (AFSS), have shown remarkable versatility and potential for various applications. Unlike conventional absorbers, AFSS can be dynamically reconfigured through external inputs, enabling switching between absorptionAbsorption and reflection modesReflection modes. This feature has driven innovations such as hyperspectral imagingHyperspectral imaging with microbolometersMicrobolometers and compressive imaging with single-pixel detectorsSingle-pixel detectors. In Intelligent Stealth Systems (ISS), highly efficient broadband absorption improves the survivability of shielded objects by minimizing reflected EM waves. Additionally, AFSS can act as ideal reflectorsReflector, allowing protected items to signal their presence even if communicationCommunication systems fail. A key development includes the integration of PIN diodes between neighbouring unit cells, achieving switchable single-band absorption/reflectionReflection, though limited to single-polarizationPolarization due to RF diode biasing complexities. Despite these challenges, some polarization-insensitive absorbersPolarization-insensitive absorbers/reflectors for single and broadbandBroadband applications have been created. Frequency Selective AbsorbersFrequency selective absorbers (FSAs) further enhance functionality by incorporating passbands or stopbands alongside absorption bands. These configurations allow low-loss signal transmissionTransmission within passbands while absorbing unwanted frequencies, though they may reduce antenna radiationRadiation efficiencyEfficiency. Conversely, notch-bandNotch-band FSAs provide excellent reflection at specific frequenciesFrequency and absorption at others, making them ideal for antenna-absorber setups and RCSRadar cross-section reduction. While various devices have been designed for specific applications, integrating all functionalities into a single device remains rare. This chapter examines the latest developments in reconfigurable absorbersAbsorber, highlighting their diverse applications and potential for future innovations.