People with psychiatric and neurological illness sometimes say and think the most amazing things. They might believe they are dead; claim to see, despite being blind; or “remember” things that never happened. Historical demarcations between academic disciplines dictate that these are distinct clinical phenomena - delusions versus confabulations; and yet each involves some distortion of reality. This special issue brings together leading researchers from diverse research fields - memory, clinical neuropsychology, psychiatry, cognitive science and philosophy - to clarify theoretical conceptions of delusion and confabulation, evaluate similarities and differences, and examine underlying causal mechanisms.