"Whether by design, accident or merely synchronicity, Checkland appears to have developed a habit of writing seminal publications near the start of each decade which establish the basis and framework for systems methodology research for that decade." Hamish Rennie, Journal of the Operational Research Society, 1992 Thirty years ago Peter Checkland set out to test whether the Systems Engineering (SE) approach, highly successful in technical problems, could be used by managers coping with the unfolding complexities of organizational life. The straightforward transfer of SE to the broader situations of management was not possible, but by insisting on a combination of systems thinking strongly linked to real-world practice Checkland and his collaborators developed an alternative approach - Soft Systems Methodology (SSM) - which enables managers of all kinds and at any level to deal with the subtleties and confusions of the situations they face. ...