Frank, you are, without doubt, a scarcity. Anyone who looks at the historical record of the juncture of art and technology finds you nearly unaccompanied when it comes to documenting this historical record between the years of the late-1960's up to the early 1990s. Basically there is you, Jack Burnham's book Beyond Modern Sculpture (1968), and Gene Youngblood's reference work Expanded Cinema (1970). Specifically, your books Origins and Development of Kinetic Art (1968), Art, Action and Participation (1975) and Art of the Electronic Age (1993) are indispensable research tools in helping us figure out how art got to where it is today - in your terms virtualized.

Joseph Nechvatal. in: "Origins of Virtualism: An Interview with Frank Popper," in: Media Art History, 2004.