2003 ACM A.M. Turing Award recipient Alan Kay was one of the driving creative forces at XEROX PARC, where he conceived of and developed the Dynabook - a powerful and portable device with a keyboard for entering information. Today's myriad portable computing devices all have roots in Kay's Dynabook, and it is for this that he is sometimes referred to as the "father of personal computers." Kay and his research team also developed SmallTalk, the first dynamic object-oriented programming language.

View Kay's lecture at 2012's ACM Turing Centenary Celebration here.

ACM A.M. Turing Award recipients Vint Cerf and Robert Kahn first met at UCLA in 1969, where they worked on the nascent ARPANET project - the technology that later became the technical foundation of the Internet. In June 1973 Kahn and Cerf invited networking experts from around the world to a seminar to weigh in on their idea of developing a system for interconnecting networks, and following this meeting, Cerf and Kahn published the seminal 1974 paper, "A Protocol for Packet Network Intercommunication" - the paper that laid the groundwork for the TCP/IP protocol and the global spread of the Internet.

Chuck Thacker's colleagues call him an "engineer's engineer." While working at Xerox PARC alongside fellow ACM A.M. Turing Award recipient Butler Lampson, Thacker was the driving creative force behind 1973's "Alto," the first system recognized as a "personal computer." Thacker moved forward from this success to make other extraordinary contributions to fields including local area networks, multiprocessor workstations, snooping cache coherence protocols, laser printing, and tablet personal computers. In 1997, he joined Microsoft Research to help establish Microsoft Research Cambridge in the UK where he was instrumental to the development of the tablet PC.

Douglas Engelbart is perhaps best known for inventing the computer mouse, though his many other contributions during the early age of computing were just as significant. Engelbart's experiences during the Second World War solidified his lifelong view of technology as a means for improving the condition of humanity, and of computers as powerful tools that could help solve the world's increasingly challenging problems. Despite his reverence for the power and potential of technology, Engelbart always maintained that the capacity for improving on improvements, or "getting better at getting better," is a uniquely human capability. Engelbart's Law, which encapsulates this principal, is named after him.

Ed Feigenbaum's lifelong interest is the question how to get computers to think, or rather, to make predictions about data as opposed to merely explaining it. While serving on the faculty at Stanford University, Feigenbaum and his colleagues developed DENDRAL, a computer program that could guess the geometrical structure of complex chemical compounds. This work convinced Feigenbaum of the enormous potential of endowing computers with "knowledge" they can use to deduce information from sets of data. Previous researchers in the realm of artificial intelligence had focused on imbuing machines with "reasoning" methods, but Feigenbaum shifted that focus to developing "knowledge" - a crucial step in the development of artificial intelligence research. 

Raj Reddy's work was instrumental in demonstrating the vast practical and commercial potential of artificial intelligence technology. Born in Katoor, Andhra Pradesh, India, Reddy earned the first computer science Ph.D ever granted by Stanford University. In 1969, he accepted an associate professorship at Carnegie Mellon University, and it was there that he developed several groundbreaking continuous speech recognition systems, including the systems Hearsay I and Hearsay II, Harpy, and Dragon, which laid the framework for most speech recognition technologies in use today. Reddy remains an active spokesperson for AI, and an active participant in many organizations in India. 

For his Ph.D thesis at MIT, Ivan Sutherland developed and described "Sketchpad," the first computer graphical user interface. The primitive TX-2 computer Sutherland used to develop Sketchpad ran "batches" of jobs and had virtually no software, but it did have a light pen which Sutherland used in a revolutionary way: to allow the user to draw directly on the computer display. In addition to being the first example of a true GUI, Sketchpad’s underlying technologies represented other breakthroughs, including hierarchical drawings and constraint-satisfaction methods. When asked how he could have done this all in the space of one year, Sutherland replied, "Well, I didn’t know it was hard."

Donald Knuth noticed something about the existing literature on computer science when he first surveyed it in 1962: it wasn't very good. An especially adept writer with an instinct for organization, Knuth took on the task of writing a concise, comprehensive text book on compilers, which later turned into an encompassing tome on computer programming. In June, 1965, the book had reached 3,000 hand-written pages, and by 1973, Knuth's work had evolved into volumes 1-3 of The Art of Computer Programming ("TAOCP"), the work that went on to become a perennial staple in computer science education. http://ow.ly/YIxPK  

In 1976, Len Adleman, Ron Rivest & Adi Shamir, then graduate students at MIT, read a paper by cryptographers Whitfield Diffie and Martin Hellman that described potential ways to send private messages in which the sender and receiver did not need a shared secret key. Inspired by this idea, the three young computer scientists went to work on developing a way to implement it, and in 1977, they published a paper demonstrating how a message could easily be encoded, sent to a recipient, and decoded with little chance of it being decoded by a third party. The “RSA” method, as it was first called, is now known as Public Key Cryptography, and its practical application cannot be understated; it is now used in almost all Internet-based commercial transactions. 

In 1958, John McCarthy and fellow Turing Laureate Marvin Minsky formed the Artificial Intelligence Project at MIT, where pioneering work took place in a wide range of fields from robotics, the theory of computation and common sense reasoning, to human-computer interfaces. At MIT, McCarthy and his colleagues made numerous critical contributions to the early advancement of Artificial Intelligence. Also during this period, inspired by advancements made by the SAGE air defense system, McCarthy then came up with a scheme for creating general purpose timesharing, the conceptual precursor to computer networking. McCarthy's work in this area was instrumental the development of the ARPAnet.

1993 ACM A.M. Turing Award co-recipients Ken Thompson and Dennis Ritchie met at the Bell Laboratories in 1966. It was there that in the span of a month, Thompson and Richie wrote the first version of the Unix operating system for a Digital Equipment Corporation PDP-7 using a cross-assembler that ran on GECOS. In 1973, at the second ACM Symposium on Operating Systems Principles, Thompson and Ritchie presented an elegant, simple, and well-written paper that described Unix, and by the end of that year there were over 20 Unix systems running. Unix went on have a far-reaching impact on its contemporary and subsequent operating systems.

When Robert Tarjan read fellow ACM A.M. Turing Award recipient Donald Knuth’s book ‘The Art of Programming,’ he was hooked on studying the analysis of algorithms. While a Ph.D candidate at Stanford, Tarjan, in collaboration with John Hopcroft developed the first linear time algorithm for planarity, which was the subject of Tarjan's Ph.D. thesis completed under the supervision of Robert W. Floyd in 1972. These techniques are now covered in most undergraduate courses in algorithm design. Tarjan and Hopcroft jointly received the Turing award for this and related work in 1986.