The concept of systems embodies the notion of a collection of elements connected together to form a whole. Systems thinking uses these notions to help understand the world. Central to this approach are the ideas of emergence and hierarchy, and communication and control. Systems practice employs systems ideas to design and manage complex processes and artefacts for the benefit of individuals, organisations, and society. Systems Theory and Practice in the Knowledge Age comprises a collection of papers written prior to the UKSS conference, that have been contributed by systems thinkers from around the world, with the aim of encouraging debate and promoting development of pertinent issues in systems theory and practice. In current times where the focus has moved from `information' to `knowledge' and where `knowledge management', `knowledge assets' and so on have become part of everyday speak, it seemed fitting to publish a book with the title of Systems Theory and Practice in the Knowledge Age.