The globalisation of markets and the expansion of product responsibility into the entire product life cycle lead to an increasing competitive situation for nationally and internationally operating companies. Therefore, to win this competition the use of the most effective and efficient resources regarding the whole product life cycle is necessary. Since these resources are globally distributed the different tasks both within a phase of product life cycle and those spread over different phases are distributed as well. The global interference of these tasks requires a close multilateral co-operation of the companies concerned. Current information- and communication technologies and modern management concepts offer high potentials to meet these requirements. The international seminar of CIRP on Life Cycle Engineering titled "Life Cycle Networks" was a forum for the presentation and discussion of current research work and recent advancements on these strategic issues for current and future engineering. Complex requirements and innovative solutions to support and realise Life Cycle Networks has been revealed and summerised. The employment of information technology to support both specific phases of product life cycle and holistic approaches will be the main focus. This volume contains the papers presented at the seminar which provide opportunities to identify the state-of-the-art and address future needs. The parts in this volume correspond to the sessions of the seminar and are presented under the following headings: Life Cycle Management; Life Cycle Design; Design for Environment; Design for Recycling; Life Cycle Assessment; Disassembly; IT-Networks.