Evolutionary Design of Electronic Circuits -- Two-Step Incremental Evolution of a Prosthetic Hand Controller Based on Digital Logic Gates -- Untidy Evolution: Evolving Messy Gates for Fault Tolerance -- Evolutionary Design Calibration -- Implementation of a Gate-Level Evolvable Hardware Chip -- A VLSI Implementation of an Analog Neural Network Suited for Genetic Algorithms -- Initial Studies of a New VLSI Field Programmable Transistor Array -- Embryonic Electronics -- An Embryonics Implementation of a Self-Replicating Universal Turing Machine -- Asynchronous Embryonics with Reconfiguration -- Embryonics: Artificial Cells Driven by Artificial DNA -- Biological-Based Systems -- A Self-Repairing and Self-Healing Electronic Watch: The BioWatch -- Shrinking the Genotype: L-systems for EHW? -- Multi-layered Defence Mechanisms: Architecture, Implementation and Demonstration of a Hardware Immune System -- Ant Circuit World: An Ant Algorithm MATLAB™ Toolbox for the Design, Visualisation and Analysis of Analogue Circuits -- Evolutionary Robotics -- Human-Like Dynamic Walking for a Biped Robot Using Genetic Algorithm -- Effect of Fitness for the Evolution of Autonomous Robots in an Open-Environment -- Incremental Evolution of Autonomous Robots for a Complex Task -- Multi-agent Robot Learning by Means of Genetic Programming: Solving an Escape Problem -- Evolutionary Optimization -- Placing and Routing Circuits on FPGAs by Means of Parallel and Distributed Genetic Programming -- A Massively Parallel Architecture for Linear Machine Code Genetic Programming -- Self-Organized Evolutionary Process in Sets of Interdependent Variables near the Midpoint of Phase Transition in K-Satisfiability -- Evolutionary Optimization of Yagi-Uda Antennas -- Evolutionary Learning -- Extraction of Design Patterns from Evolutionary Algorithms Using Case-Based Reasoning -- Balancing Samples’ Contributions on GA Learning -- Solving Partially Observable Problems by Evolution and Learning of Finite State Machines -- GA-Based Learning of kDNF n s Boolean Formulas -- Applications -- Polymorphic Electronics -- Initial Experiments of Reconfigurable Sensor Adapted by Evolution -- A Lossless Compression Method for Halftone Images Using Evolvable Hardware -- Evolvable Optical Systems and Their Applications.

On behalf of the ICES 2001 Conference Committee, it is our pleasure to present to you the proceedings of the fourth International Conference on Evolvable S- tems: From Biology to Hardware, ICES 2001, held in Tokyo, Japan, on 3-5 - tober 2001, addressing the latest developments and discussing challenges facing the ?eld of evolvable systems. The idea of evolving machines, whose origins can be traced back to the - bernetics movement of the 1940s and the 1950s, has recently re-emerged in the form of the nascent ?eld of bio-inspired systems and evolvable hardware. Foll- ing the workshop, Towards Evolvable Hardware, which took place in Lausanne, Switzerland, in October 1995, the First International Conference on Evolvable Systems: From Biology to Hardware (ICES96), was held at the Electrotech- cal Laboratory (MITI), Tsukuba, Japan, in October 1996. The second and the third International Conferences on Evolvable Systems: From Biology to Ha- ware (ICES98 and ICES 2000) were respectively held in Lausanne in September 1998, and in Edinburgh in April 2000. Following the success of these past events, ICES 2001 was dedicated to the promotion and advancement of all aspects of evolvable systems, including ha- ware, software, algorithms, and applications. By bringing together researchers who use biologically inspired concepts to implement real systems in arti?cial - telligence, arti?cial life, robotics, VLSI design, and related domains, ICES 2001 reunited this burgeoning community.