Kepler's Somnium is a fantastical story about the world on the moon. It presents a heliocentric world-picture established through a total conversion of the meaning and place of observation in the hierarchy of knowledge. This epistemological program is construed through a critical adaptation of Lucian's "True Story," and Plutarch's "The Face on the Moon." Utilizing his new optics, embodied in the Camera obscura, Kepler inverts the meaning of these classical texts together with the reader's point of view. Astronomical knowledge is vindicated and scientific observation is the only way out of an obscure and mannerist dream.