The daily routine changed: instead of going to the University each day, where I used to spend most of my time in the company of others, I now went there only one day a week and was most of the time -that is, when not travelling!- alone in my study. In my solitude, mail and the written word in general became more and more important. The circumstance that my employer and I had the Atlantic Ocean between us was a further incentive to keep a fairly complete record of what I was doing. The public part of that output found its place in what became known as "the EWD series," which can be viewed as a form of scientific correspondence, possible since the advent of the copier. (That same copier makes it hard to estimate its actual distribution: I myself made about two dozen copies of my texts, but their recipients were welcome to act as further nodes of the distribution tree. ) The decision to publish a se1ection from the EWD series in book form was at first highly embarrassing, but as the months went by I got used to the idea. As soon as some guiding principles had been adopted -preferably not published elsewhere, as varied and as representative as possible, etc.

    

    The results presented are related to the underlying methodology. Each chapter is introduced by a short note outlining the scope of the problem begin taken up or placing it in its historical context.Contents, Volume II: Understanding Vision: Representing and Computing Visual Information; Visual Detection of Light Sources; Representing and Analyzing Surface Orientation; Registering Real Images Using Synthetic Images; Analyzing Curved Surfaces Using Reflectance Map Techniques; Analysis of Scenes from a Moving Viewpoint; Manipulation and Productivity Technology: Force Feedback in Precise Assembly Tasks; A Language for Automatic Mechanical Assembly; Kinematics, Statics, and Dynamics of Two-Dimensional Manipulators; Understanding Manipulator Control by Synthesizing Human Handwriting; Computer Design and Symbol Manipulation: The LISP Machine; Shallow Binding in LISP 1.5; Optimizing Allocation and Garbage Collection of Spaces; Compiler Optimization Based on Viewing LAMBDA as RENAME Plus GOTO; Control Structure as Patterns of Passing Messages.

    The results presented are related to the underlying methodology. Each chapter is introduced by a short note outlining the scope of the problem begin taken up or placing it in its historical context.Contents, Volume I: Expert Problem Solving: Qualitative and Quantitative Reasoning in Classical Mechanics; Problem Solving About Electrical Circuits; Explicit Control of Reasoning; A Glimpse of Truth Maintenance; Design of a Programmer's Apprentice; Natural Language Understanding and Intelligent Computer Coaches: A Theory of Syntactic Recognition for Natural Language; Disambiguating References and Interpreting Sentence Purpose in Discourse; Using Frames in Scheduling; Developing Support Systems for Information Analysis; Planning and Debugging in Elementary Programming; Representation and Learning: Learning by Creating and Justifying Transfer Frames; Descriptions and the Specialization of Concept; The Society Theory of Thinking; Representing and Using Real-World Knowledge.

    Gersting's text binds together what otherwise appears to be a collection of disjointed topics by emphasizing the following themes: • Importance of logical thinking• Power of mathematical notation• Usefulness of abstractions

    Yet, ironically, many of its basic results were discovered by mathematical logicians prior to the development of the first stored-program computer. As a result, many texts on computability theory strike today's computer science students as far removed from their concerns. To remedy this, we base our approach to computability on the language of while-programs, a lean subset of PASCAL, and postpone consideration of such classic models as Turing machines, string-rewriting systems, and p. -recursive functions till the final chapter. Moreover, we balance the presentation of un solvability results such as the unsolvability of the Halting Problem with a presentation of the positive results of modern programming methodology, including the use of proof rules, and the denotational semantics of programs. Computer science seeks to provide a scientific basis for the study of information processing, the solution of problems by algorithms, and the design and programming of computers. The last 40 years have seen increasing sophistication in the science, in the microelectronics which has made machines of staggering complexity economically feasible, in the advances in programming methodology which allow immense programs to be designed with increasing speed and reduced error, and in the develop ment of mathematical techniques to allow the rigorous specification of program, process, and machine."