PANKAJ JAIN is associate professor of Mathematics at the South Asian University, New Delhi, India. With over 27 years of teaching experience, Dr Jain has taught several courses in pure and applied mathematics both at undergraduate and postgraduate levels. His research interests include the theory of function spaces, integral inequalities of Hardy type and Fourier analysis. He has authored more than 50 research papers in several respected international journals. Dr Jain has been involved in 23 collaborations, including 12 from outside India. Dr Jain has received grants from various agencies in India and abroad in connection with research projects, attending international conferences and collaborating with foreign mathematicians. This includes the BOYSCAST fellowship of DST visiting Sweden, the Royal Society (London) Exchange Programme visiting the U.K. three times and very recently the Indo-Russian S&T project.HANS-JÜRGEN SCHMEISSER is professor of Analysis at the Friedrich Schiller University of Jena, Germany. His research fields include the theory of function spaces as well as Fourier analysis and approximation theory. He has published a joint monograph with Hans Triebel on ＂Topics in Fourier Analysis and Function Spaces＂ and about 60 research papers with 12 coauthors. He is one of the organisers of the international conference series on ＂Function Spaces, Differential Operators and Nonlinear Analysis (FSDONA)＂. His research has received several grants from the German Research Foundation (DFG).