How did Champollion succeeded in deciphering the hieroglyphics? The letters he wrote regularly to his brother and thousands of working notes shed light on its path, its difficulties and its brilliant intuitions, excerpts are presented here, around the Rosetta Stone. His letters also allow us to follow the researcher in his expedition on the banks of the Nile and explore with him the ancient Egyptian gods with multiple faces, the mummies and furniture that accompanied them in the Hereafter.