What is the theme in 2061: Odyssey Three by Arthur C. Clarke?

The novel carries common themes of Clarke's science fiction: exploring the place of humans in the universe; learning to extend the life span of an individual human being; using technology to improve the quality of life for society encountering extraterrestrial life forms, both primitive and superior to humans; adapting lifestyles and even evolving into transformed beings with more extensive powers in the context of travel to new environments in the solar system and galaxy.