• 28 Books

• 4 Interplanetary voyages
• 3 Prefect, Ford
• 2 Artificial intelligence
• 2 Dent, Arthur (Fictitious character)
• 2 Human-alien encounters
• 2 Imaginary wars and battles
• 2 Life on other planets
• 2 Scientists
• 2 Time travel
• 2 Utopias
• 1 Astronauts
• 1 Astronomers
• 1 Books
• 1 Citizen participation
• 1 Colonists
• 1 Colonization
• 1 Communicable diseases
• 1 Computer simulation
• 1 Computers and civilization
• 1 Core
• 1 Dent, Arthur
• 1 Digitization
• 1 Effect of human beings on
• 1 End of the world
• 1 Environmental protection

• 4 Izquierdo, Maritza
• 3 Wells, H. G. (Herbert George), 1866-1946
• 2 Adams, Douglas, 1952-2001
• 2 Clarke, Arthur C. (Arthur Charles), 1917-2008
• 2 Gómez Ibáñez, Benito
• 2 López, Norma B. de
• 2 Verne, Jules, 1828-1905
• 2 Zilli, Edith
• 1 Alou, Damián, 1959-
• 1 Ammaniti, Niccolò, 1966-
• 1 Artacho Martín, Lola
• 1 Asimov, Isaac, 1920-1992
• 1 Barby, Ralph
• 1 Bellamy, Edward, 1850-1898
• 1 Besa, Luis, 1965-
• 1 Bierce, Ambrose, 1842-1914?
• 1 Bosch Barrett, Manuel
• 1 Butler, Samuel, 1835-1902
• 1 Castelló, Alfonso
• 1 Chicagui L., Julio Ernesto (Chicagui Larrotta)
• 1 Colfer, Eoin
• 1 Cotarelo Jiménez, Andrés
• 1 Cotarelo, Alicia
• 1 Cotarelo, Ramón, 1943-

• 27 Spanish
• 1 English

• 2 Earth (Planet)
• 2 Mars (Planet)
• 2 Moon
• 1 Boston (Mass.)
• 1 Easter Island
• 1 Florence (Italy)
• 1 London (England)
• 1 Sicily (Italy)

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