Relativity, Space and Time - Science popularization article on the Theory of Relativity. - http://pgostrov.googlepages.com/e2.html
Cambridge Relativity Public Home Page - Various pages with non-technical texts about cosmology, black holes, cosmic strings, inflation, quantum cosmology, and string theory, written by members of the Relativity Group at Cambridge University. - http://www.damtp.cam.ac.uk/user/gr/public/
Selected References in Relativistic Cosmology and General Relativity - Extensive list of classic and modern research papers in cosmology and general relativity. Although the author warns that his selection is subjective, the result is a highly useful list of references; for many papers, there are links to online versions on - http://www.maths.qmul.ac.uk/~hve/paplist.html
Subtle is the Gravity - Review of the motivations for and basic principles of general relativity, aimed at a general audience. Written by Naresh Dadhich (IUCAA Pune), based on a lecture delivered in 2001. - http://arxiv.org/abs/gr-qc/0102009
Numerical Relativity: Status and Prospects - Review article by Luis Lehner about the foundations of numerical relativity and recent progress in the field; particular attention is paid to simulations of black hole spacetimes. - http://arxiv.org/abs/gr-qc/0202055
Wikipedia: Introduction to General Relativity - Encyclopedia article explaining the basic concepts, observational tests and (astrophysical) applications of general relativity. - http://en.wikipedia.org/wiki/Introduction_to_general_relativity
Wikipedia: General Relativity Resources - Annotated list of reading material about general relativity: popular books, textbooks, books on specific topics, web courses, and websites. - http://en.wikipedia.org/wiki/General_relativity_resources
The Light Cone: An Illuminating Introduction to Relativity - Introduces the basic principles of relativity, the physics of special relativity, and some basic principles of general relativity. Contains a great number of helpful images and animations; site created by Rob Salgado (Syracuse University). - http://www.phy.syr.edu/courses/modules/LIGHTCONE/
Introduction to General Relativity - By Gerard 't Hooft (Utrecht University); based on lectures held in 2002; a thorough introduction starting with accelerated frames and including topics such as black holes, the basics of cosmology, and gravitational radiation. - http://www.phys.uu.nl/~thooft/lectures/gr.html
Interactive Geometric Database - Interactive database developed by Mustapha Ishak and Kayll Lake and hosted by Queen's University; allows the user to search for specific solutions of Einstein's field equations (that is, for specific model universes of general relativity). - http://130.15.26.66/servlet/GRDB2.GRDBServlet
Einstein Online - Information about Einstein's theories of special and general relativity and their applications; site is hosted by the Max Planck Institute for Gravitational Physics. Includes a simple introduction, a collection of articles ("Spotlights on relativity& - http://www.einstein-online.info/en
Are There Any Good Books on Relativity Theory? - The Physics FAQ's guide to relativity books; by Chris Hillman (with contributions by Nathan Urban). An extensive annotated list of semi-popular books, textbooks and background reading. - http://math.ucr.edu/home/baez/physics/Administrivia/rel_booklist.html
General Relativity Simulation Contest - Attempt at a content aimed at the Internet community to write a simulation program, based on a simple algorithm incorporating the laws of general relativity, that can realistically simulate the behavior of black holes, binary stars, and the twin paradox. - http://users.telenet.be/nicvroom/contest.htm
Relativity - Provides information on the history, experiments and paradoxes of relativity. - http://nobelprize.org/physics/educational/relativity/
An Essay on General Relativity - Overview of the basic ideas and principal applications of general relativity. Written by John L. Safko for students in the self-paced astronomy courses at the University of South Carolina in 1997. - http://astro.physics.sc.edu/selfpacedunits/Unit57.html
Relativity: List of Important Equations - Page scans from the Handbook of Space Astronomy and Astrophysics giving equations and formulas for special relativity and relativistic cosmology. Includes bibliography. - http://ads.harvard.edu/books/hsaa/chap10.html
Physics Bookshelf - Relativity - A collection of articles about relativity - http://www.upscale.utoronto.ca/GeneralInterest/Relativity.html
Interactive Experiments in Gravity - Try an experiment that illustrates the gravitational attraction between two objects or use a Java applet to understand how orbits work in strongly curved space-time. - http://www.fourmilab.ch/gravitation/
NOVA Online/Einstein Revealed - Profile of Albert Einstein, with additional teaching resources, Shockwave demonstrations, and animations of relativity concepts. - http://www.pbs.org/wgbh/nova/einstein/
Relativity bookmarks - Large collection of relativity-related links by Rob Salgado (Syracuse University). Warning: page hasn't been updated since 2000, and quite a number of links are now broken. - http://physics.syr.edu/research/relativity/RELATIVITY.html
QMW Hyperspace - A set of hypertext based services for general relativity research provided by the QMW Relativity group. - http://www.maths.qmw.ac.uk/hyperspace/