Prof. Vaidyanathan, was born in October 1931. He was educated in Madras, and did post graduate studies in the USA. After obtaining a Ph D from Cornell University, he worked for a few years (1956-62) as economist in the National Council of Applied Economic Research, New Delhi before joining the Perspective Planning Division of the Planning Commission.

After 10 years in the Planning Commission, and 3-4 years in the World Bank, he was professor at the Centre for Development Studies, Trivandrum for 8 years. He moved to MIDS in 1984. After retirement in 1991, he continued as Emeritus professor till March 2005 when he relinquished the position.

Prof Vaidyanathan's research is concerned mostly with empirical analysis and interpretation of various aspects of Indian economy and society. He has studied and written on issues concerning planning and development strategy, agricultural and bovine economy, irrigation and water management, employment, poverty and quality of socio economic data. Besides academic publications, he has written extensively on policy issues and is an active participant in public discussions on these matters. His publications include 'India’s Agricultural Development in a Regional Perspective', 'Performance of Indian Agriculture since Independence'; a critique of economic reforms titled 'Indian Economy: Crisis, Response and Prospects' and an edited collection on 'Elementary Education in India: A Grassroots perspective'.

In recent years he has concentrated on water related issues. Besides a book 'Water Resource Management: Institutions and Irrigation in India', two collections - 'Tanks of South India' and 'Managing Water Scarcity: Experiences and Lessons' - edited by him are under publication. He is actively associated with the efforts of the Centre for Science and Environment to preserve and restore the tradition of community management of water and promote community based rainwater harvesting in rural and urban areas.

Prof Vaidyanathan has served on a number of Government Committees: he was chairperson a Committee on irrigation pricing set up by the Planning Commission, served briefly as member of the Planning Commission in New Delhi and of the Tamilnadu State planning commission. He chairs a Taskforce on restructuring and revitalisation of cooperative credit structure appointed by the Ministry of Finance. The Task force's report on the short term structure ha been submitted and accepted in principle by the GOI. Work on long term credit is in process.

He has been president of the Indian Society of Agricultural Economics;

Chairperson of the Governing Council of the Centre for Development Studies, Thirvanathapuram.

He is currently Chairperson of the institute of Social Studies Trust, New Delhi and a member of the board of governors of the Institute for Social and Economic Change, Bangalore.