Recently, the field of animal memory research has seen a resurgence of interest in the mechanisms underlying retrograde amnesia (RA) and in the use of RA as a technique for studying memory processes. A recent report from a major neuroscience lab, which demonstrated RA for an old reactivated memory, revitalized the debate regarding the widely accepted memory-consolidation theory of RA. Here, we discuss a number of the characteristics of RA and consider the findings that led to the development of the memory-consolidation hypothesis, as well as those suggesting an alternative retrievaldeficit explanation.