This book presents a theory as well as methods to understand and to purposively influence
complex systems. It suggests a theory of complex systems as nested systems i. e. systems that
enclose other systems and that are simultaneously enclosed by even other systems. According to
the theory presented each enclosing system emerges through time from the generative activities
of the systems they enclose. Systems are nested and often emerge unplanned and every system of
high dynamics is enclosed by a system of slower dynamics. An understanding of systems with
faster dynamics which are always guided by systems of slower dynamics opens up not only new
ways to understanding systems but also to effectively influence them. The aim and subject of
this book is to lay out these thoughts and explain their relevance to the purposive development
of complex systems which are exemplified in case studies from an urban system. The interested
reader who is not required to be familiar with system-theoretical concepts or with theories of
emergence will be guided through the development of a theory of emergent nested systems. The
reader will also learn about new ways to influence the course of events - even though the
course of events is in principle unpredictable due to the ever-new emergence of real
novelty.
