Everything we know is mediated by our senses: there is always something we don't see, don't perceive, or ignore. Reality can change from one moment to the next... Nine stories, fantastic and sci-fi, to do a “reality check”, a check on the effectiveness of things: stories that reveal hidden truths, or imagine worlds similar to ours, but at the same substantially different time. Nine stories that develop the classic “what if” theme, declining it with respect to the past, present or future. For more information on THE EXACT PERCEPTION, please refer to the website of the association RiLuce di Luce Lunar, who edited the book: https://rill.it/l-esatta-percezione Andrea Viscusi was born in 1986. His fantastic and science fiction stories have been awarded in many literary competitions and have been published in anthologies and magazines. He has published the novels “Forget Me Find Me Sognami” (2015) and “Symphony for Theremin and Blackbirds” (2021), published by Zona42.