Credit is given to the following sources for photographs:

Cover: Silhouette of couple: Zoonar/Sergey Peterm/AGE fotostock; top row (from left): Enceladus ice geysers: Cassini Imaging Team, SSI, JPL, ESA, NASA; Helix Nebula: NASA/JPL-Caltech/Univ. of Arizona; Sombrero Galaxy: NASA/JPL-Caltech/R. Kennicutt (University of Arizona) and the SINGS Team; planetary nebula MyCn18: Raghvendra Sahai and John Trauger (JPL), the WFPC2 science team, and NASA; second row: Rings 747828 (NASA identifier: C-1981-4319): NASA; Big Blue Marble: GSFC/NASA; Crab Nebula: NASA, ESA, J. Hester, A. Loll (ASU); pillar and jets (HH 901/902): NASA, ESA, M. Livio, and the Hubble 20th Anniversary Team (STScl); third row: Cat’s Eye Nebula: NASA/UIUC/Y. Chu et al., optical: NASA/HST; solar prominence: SOHO/Extreme Ultraviolet Imaging Telescope, ESA, NASA; The Lunar Far Side: The Side Never Seen from Earth: NASA/Goddard; Hale Bopp: Andrew M. Sorenson; fourth row: Bug Nebula (NGC 6302): NASA, ESA, and the Hubble SM4 ERO Team; Pillars of Creation: NASA, ESA, STScI, J. Hester and P. Scowen (Arizona State University); Eye-Shaped Planetary Nebula (NGC 6826): Bruce Balick (University of Washington), Jason Alexander (University of Washington), Arsen Hajian (U.S. Naval Observatory), Yervant Terzian (Cornell University), Mario Perinotto (University of Florence, Italy), Patrizio Patriarchi (Arcetri Observatory, Italy) and NASA; Eskimo Nebula: NASA, Andrew Fruchter and the ERO Team, Sylvia Baggett (STScI), Richard Hook (ST-ECF), Zoltan Levay (STScI); fifth row: Jupiter and its satellites: NASA, ESA, and E. Karkoschka (University of Arizona); Cartwheel Nebula: NASA/JPL-Caltech; Mountains of Creation region: infrared data taken by NASA’s Spitzer Space Telescope, NASA/JPL-Caltech/L. Allen (Harvard-Smithsonian CfA); Whirlpool Nebula (M51): NASA/CXC, ultraviolet: NASA/JPL-Caltech, optical: NASA/ESA/STScI/AURA, infrared: NASA/JPL-Caltech/Univ. of Arizona.

Title Page: (from left) Cat’s Eye Nebula: NASA/UIUC/Y. Chu et al., optical: NASA/HST; solar prominence: SOHO/Extreme Ultraviolet Imaging Telescope, ESA, NASA; The Lunar Far Side: The Side Never Seen from Earth: NASA/Goddard; Hale Bopp: Andrew M. Sorenson; Enceladus ice geysers: Cassini Imaging Team, SSI, JPL, ESA, NASA; Helix Nebula: NASA/JPL-Caltech/Univ. of Arizona; Sombrero Galaxy: NASA/JPL-Caltech/R. Kennicutt (University of Arizona) and the SINGS Team.

Cosmic Connections: p. 16: Sun: NOAO/NASA; galaxies: Hubble Heritage Team (STScI/AURA)/NASA; Earth: NASA Goddard Space Flight Center, image by Reto Stöckli; galaxy clusters: NOAO/NASA; Milky Way: NASA/JPL-Caltech/R. Hurt (SSC); galaxy map: T. H. Jarrett, J. Carpenter, & R. Hurt/2MASS; pp. 192–193: NASA; p. 260: Courtesy of Lunar and Planetary Institute/USRA; p. 303: NASA; p. 341: NASA; p. 389: NASA; p. 413: A killer asteroid, from “The Day the World Burned” by D. A. Kring and D. D. Durda, Scientific American, December 2003, art by Chris Butler; p. 437: Sun: NOAO; Leonids: Walter Pacholka, Astropics/Science Source; p. 622: NASA; p. 655: spiral galaxy: NASA and ESA; globular cluster: S. Kafka and K. Honeycutt, Indiana University/WIYN/NOAO/NSF; p. 690: 1. Bob and Bill Twardy/Adam Block/NOAO/AURA/NSF; 2. NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration; 3. NASA/JPL-Caltech/Z. Wang (Harvard-Smithsonian CfA); p. 709: top: Accretion disks, Alfred T. Kamajian; bottom: Accretion disk simulation, Michael Owen and John Bondin, North Carolina State University.