This Topic in Depth presents the science and research of galaxies. First, the University of Cambridge offers clear, logical descriptions and images of the Milky Way, spiral and elliptical galaxies, clusters, and dark matter of the Universe (1). Users can also find educational tutorials on many other cosmology topics. Next, the Space Telescope Science Institute's "Galaxies Galore, Games and More is a learning module designed to allow elementary students to use their observational skills, recognize patterns, and learn how galaxies are classified" (2). Through the fun, interactive materials, students can learn about spiral, elliptical, and irregular galaxies. The third website, developed by NASA, introduces students to Seyfert Galaxies, quasars, and blazars (3). Visitors can find cool facts about the topic, quizzes, an advanced-level article on galaxies and pulsars, and additional resources. Next, Professor Bill Keel at Leiden University and the University of Alabama supplies graduate level virtual lectures on the topic of extragalactic astronomy (4). While the website is only updated to the most recent class he taught (Spring of 2003), the wealth of high-quality information offered on topics such as star formation, environmental effects on galaxies, and galaxy interactions and mergers makes it worth the visit. The fifth website, produced by the Jodrell Bank Observatory, is "an electronic publication dedicated to the observations and theory of active galaxies" (5). The newsletter promotes new papers, conferences, dissertations, employment opportunities, and more. Sixth, the Science Museum of Virginia educates users about the differences among galaxies through a series of images and clear text (6). Visitors can view images collected by the Hubble telescope and can test their skills at classifying galaxies. The seventh website, produced by National Academy of Engineering member Edward Barlow, presents concepts of general relativity and the new developments and tools used to study galaxies and other cosmological phenomena (7). The complex materials offer great examples of how models are used to help scientists understand facets of the universe. Lastly, Wikipedia offers concise explanations of the characteristics of galaxies, their history, and etymology (8). Throughout the text, visitors can find links to more information on the concepts discussed.