Andrzej Pitrus analyzes and interprets Bill Viola’s tape "Memory Surfaces and Mental Prayers" (1977). The cycle was created as one of the earlier works by Viola, and deals with the issue of perception. The artist also refers to his fascination with cultures, philosophy, and religions of the East. All three pieces included in the tape are discussed: "The Wheel of Becoming", "The Morning After the Night of Power" and "Sweet Light". Each of them uses different techniques and creative strategies to explore the medium, which was a relatively new artistic tool in the second part of the seventies. Bill Viola’s work seems to be quite unique as it combines explorations of technology with musings about the very nature of human perception. The artist is quite convinced that a human being is not able to see the world as it really is. His perception is limited both by his own senses, and technologies he creates and uses.