First chapter of “Creatures of Light And Darkness.” Roger Zelazny. A god controls a gladiator’s mind and removes all memories of his past.

TV show ‘The Prisoner.’ Psychoman episode. The bad guys convince a man he is someone else, then tell him he needs to pretend to be the man he was.

“Eternal Sunshine Of the Spotless Mind” Never seen it myself, but the plot involves getting memory wipes to get over bad relationships.

“We Can Remember It For You Wholesale” by Philip K. Dick. Basis of the movie ‘Total Recall.’

“The Forever War.” Joe Haldeman. In order to train soldiers quickly, the troops are dropped into tanks where they ‘live’ other lives. You are a Zulu warrior fighting with spears, or a Hessian cavalryman, or a Burmese partisan.