Rigor mortis is certainly the most fascinating cadaveric sign. Because it gives the deceased person a petrified appearance, rigor mortis is noticed by everybody who encounters a corpse. It is therefore often used to estimate the time since death, even (and especially) by the non-initiated. It is generally accepted that a watch must be tested, perhaps even under various circumstances, before it is used to measure time. In addition, one is expected to read the user’s manual. Alas, I fear we lack such a user’s manual in the case of rigor mortis – and, if this is so, it is certainly not for want of related literature; in fact, publications about cadaveric rigidity abound. A brief summary of our present knowledge concerning this phenomenon is presented here.