In Arthur C. Clarke's Space Odyssey series, Monoliths are machines in black cuboids whose sides extend in the precise ratio of 1 : 4 : 9 (12 : 22 : 32) built by an unseen extraterrestrial species whom Clarke dubbed the Firstborn and whom he suggests are the earliest highly intelligent species to evolve in the Milky Way. In the series of novels (and the films based on these), three Monoliths are discovered in the Solar System by australopithecines and their human descendants. The response of the characters to their discovery drives the plot of the series. It also influences the fictional history of the series, particularly by encouraging humanity to progress with technological development. The first Monolith appears at the beginning of the story, set four million years before the present era. It is discovered by a group of australopithecines and triggers a shift in evolution, starting with the ability to use tools and weaponry. It is later revealed that thousands of other Monoliths exist elsewhere in the galaxy. Origins The species that built the Monoliths is never described in detail, but some knowledge of its existence is given to Dave Bowman after he is transported by the star-gate to the "cosmic zoo", as detailed in the 1968 novel 2001: A Space Odyssey and its 1982 sequel, 2010: Odyssey Two. The existence of this species is only hypothesized by the rest of humanity, but it is obvious because the Monolith was immediately identified as an artefact of non-human origin. The species that built the Monoliths developed interstellar travel millions or perhaps billions of years before the present time. In the novels, Clarke refers to them as the "Firstborn", since they were quite possibly the first sapient species to possess a significant capability of interstellar travel. Members of this species explored the universe in the search of knowledge, especially knowledge about other intelligent species. While these early explorers discovered that life was quite common, they observed that intelligent life was often stunted in its development, or else died out prematurely. Hence, they set about fostering it. Though not at all morphologically similar to humans, the Firstborn were nonetheless creatures of "flesh and blood", and like humans, were originally mortal. However, the evolutionary development projects they began would by their nature require very long time-spans to complete, far longer than the lives of their creators. Therefore, the aliens created increasingly complex