Revision with unchanged content. This book explores design tools based on evolutionary computation (EC), oriented primarily toward conceptual design of architectural and civil en­ginee­ring structures. EC tools are well suited for exploration in a way which pro­motes creative design. The multiplicity of solutions generated by EC tech­niques is less likely to cause design fixation, and so promote a more thorough ex­plo­ration of possible solutions. The use of such tools also allows the de­si­g­ner greater latitude in exploring design criteria, such as aesthetics, by utilizing an interactive human-computer interface. This book begins with a survey of tech­niques that have been used in early phases of architectural design, and estab­lishes a set of successful attributes, which are then discussed in the con­text of EC techniques. Finally, a specific implementation developed by the au­thor is described. Several examples are given in the area of architectural en­gi­nee­ring, and comparisons are made with results obtained with more con­ven­tio­nal optimization tools. This book is especially useful for designers in­ter­es­ted in new methods for generating and exploring structural form, and is acces­sible to non-programmers in either field.