Igor Kluvánek made significant contributions to applied mathematics, functional analysis, operator theory and vector-valued integration. One needs only to consult his book Vector Measures and Control Systems written with Greg Knowles or examine the contents and historical notes of the monograph Vector Measures by J. Diestel and J.J. Uhl, Jr., to see that his penetrating studies into this area, of which he is one of the pioneers, pervade the subject. He has also made important contributions to various topics in harmonic analysis. For a sample of his influence in this area, see the excellent survey article "Five short stories about the cardinal series", Bull. Amer. Math. Soc., 12 (1985), 45–89, by J.R. Higgins which highlights the essential role played by just one of Kluvánek's paper in the "story" of the sampling theorem. Kluvánek introduced the concept of a closed vector measure. This notion was crucial for his investigations of the range of a vector measure and led to the extension to infinite dimensional spaces of the classical Liapunov convexity theorem, together with many consequences and applications. This work was in collaboration with G. Knowles and settled many of the major problems in this area. The notion of a closed vector measure stimulated much research, especially by W. Graves and his students at Chapel Hill, North Carolina. In intervening years it turned out that this notion is not only a basic tool in the study of algebras of operators generated by Boolean algebras of projections but lies at the very core of the major theorems in this area, even throwing a new perspective on the classical results in this field.