Using polarimetry as a tool to study high-energy photons was until now rather uncommon. Recent satellite measurements proved the high power of polarization observables and initiated a rapid development of new instruments. We describe the physical mechanisms leading to photon polarization, and discuss the processes used for its detection at energies from few kiloelectronvolts X-rays up to megaelectronvolts γ-rays. Past attempts and instrumentation applied for polarization measurements are

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... zed and reviewed with respect to experimental difficulties. We also present current and planned polarimeters and the utilization of novel, energy specific, detection technologies. Finally, we discuss the importance of proper modelling and calibration of the polarimeter, and describe several methods used to characterize it.