  Silicon photomultipliers, thanks to their excellent performance, robustness
and relatively simple use, are the photon-detectors of choice for many present
and future applications. This paper gives an overview of methods to
characterise SiPMs. The different SiPM parameters are introduced and generic
setups for their determination presented. Finally, ways to extract the
parameters from the measurements are discussed and the results shown. If a
parameter can be obtained from different measurements, the results are compared
and recommendations given, which is considered to be the most reliable. The
characterisation of SiPMs, in particular for high light intensities and in high
radiation fields, is presently a field of intensive research with many open
questions and problems which will be discussed.
