[2] From 1992 to 1998, he was a board member of the Indo–Dutch Programme for Alternatives in Development (IDPAD) and the J. Gonda Stichting of the Royal Netherlands Academy of Arts and Sciences (KNAW).
[5] Jan C. Heesterman [it] noted that the research interests of Kolff included "India's muslim rulers" and "the working and enduring vitality" of the dynamics of Mughal Empire.
Heesterman wrote, "focussing attention on India's 'armed peasantry' in its various guises of both sedentary 'ryots' and itinerant warriors, Kolff brings out the flexibility and dynamics of the Mughal world that was known to its European contemporaries as the 'flourishing Indies'."
According to John F. Richards of the Duke University, his research is of assistance in underscoring "the magnitude of the changes wrought in Indian society by violent British conquest, pacification and disarmament in rural society—especially after the failed 1857 revolt".
Kolff coined the term "military labour market", and in the book, introduced this concept on a wide scale in context of the northern region of India.
According to University of Cambridge's Randolf G. S. Cooper, Kolff clarified the "understanding of the way in which military service had a life cycle or commodity exchange value that was integral to South Asian society and realpolitik".
Cooper further stated that Kolff's work is of assistance in breaking the stereotypical image of the Rajputs as "the saffron robed warrior prince on horseback".