While Cradle works the concept of contact with extraterrestrials in the relatively "near future" and uses a plausibly "here and now" perspective of life in Miami and the Florida coastal waters, Clarke and Gentry Lee's Rama tetralogy — Rendezvous with Rama (1973), Rama II (1989), The Garden of Rama (1991), and Rama Revealed (1994) — develop a "far future" (twenty-second and twenty-third century) saga of humanity's expanding horizons via contacts with mysterious and highly advanced beings which are surveying the galaxy to catalog and observe the various species which have achieved space travel in some form.

The contacts involve several sets of characters and multiple encounters, first within the solar system but, thereafter, en route across the galaxy. While other species which have been "collected" for study are eventually understood by the main characters in the latter two novels in the series, and certain perspectives on the breadth of the...