There was an excellent cs theory stack exchange question on this: http://cstheory.stackexchange.com/questions/1168/what-papers-should-everyone-read http://csth

There was an excellent cs theory stack exchange question on this: http://cstheory.stackexchange.com/questions/1168/what-papers-should-everyone-read http://cstheory.stackexchange.com/questions/1168/what-papers... [pdf] The top two are nearly tied for: "A mathematical theory of communication" by Claude Shannon http://guohanwei.51.net/code/A%20Mathematical%20Theory%20of%20Communication.pdf http://guohanwei.51.net/code/A%20Mathematical%20Theory%20of%... "On Computable Numbers, with an Application to the Entscheidungsproblem" by Alan Turing http://l3d.cs.colorado.edu/~ctg/classes/lib/canon/turing-compnum.pdf http://l3d.cs.colorado.edu/~ctg/classes/lib/canon/turing-com... [pdf] I would add that 'The Annotated Turing' by Charles Petzold http://www.theannotatedturing.com/ http://www.theannotatedturing.com/ is an excellent treatment of Turings paper, including much of the relevant additional math and computing history both before and after.