Anyone interested in systems thinking should consult the seminal works of Professor Peter Checkland (Lancaster University, UK) whose book Systems Thinking, Systems Practice is a good introduction to all the fundamental principles of systems including a key element not mentioned anywhere in this article - the recognition that complex systems may present hitherto unexpected emergent properties. Checkland's work builds on the foundations set by Stafford Beer a few decades earlier, whose work on the science of cybernetics was ground-breaking.