The paper covers the area of systems thinking and practice in manageme
nt consultancy primarily in Tata Consultancy Service in India. As the
largest consultancy organization in the country, it has the need and o
pportunity to deal with very large societal systems which are by natur
e complex. It needs to develop new holistic approaches to execute the
assignments. The Systems Engineering and Cybernetic Centre (SECC) was
started in 1982 to meet this requirement. The paper described the gene
sis and the arena of activity of SECC over the years, highlighting the
formulation of an interactive consulting paradigm and a multimodeling
approach to complex problem solving. The philosophical bases of these
are discussed along with systems practice in some typical complex ass
ignments.