Nowadays we would use 3D imaging software to create the Galactic Lens. But as with the Prime Radiant, Asimov gives little idea of the underlying technology of the Galactic Lens. Only this is no ordinary slide rule. Without computers and networks, the communications technology of the trilogy sometimes comes across as amusingly clunky. No electronic messaging, no idea of a paperless office.
Messages arrive in capsules, shot through tubes or teleported through hyper-space.
Arkady speaks into the machine, and it prints out her words in a fancy calligraphic font. Although Asimov surely had no conception of a personal computer in the days he wrote these books, a form of fax machine had been around for many years, no doubt providing the germ of Arkady's transcriber. Computers are ubiquitous and often mentioned. Asimov introduces an immersive computing experience leaning toward Gibsonesque cyberspace. In fact, what it does is to force me to think about our own current visions of the future.