Dr Henk G. Merkus has been working at Delft University of Technology for about 35 years, the last 20 years of it in Particle Characterization in the Particle Technology Group of prof. Brian Scarlett. Also, for about 15 years he has been a member of ISO/TC24 on Sieving and Other Methods for Particle Size Measurement and he still is. Retired now the author is active in giving courses on this subject, in the Netherlands as well as in Sweden and the United Kingdom. Dr Merkus is the author of the Springer book “Particle Size Measurements” (2009). Dr Ir Gabriel M.H. Meesters is affiliated to DSM Food Specialities and Delft University of Technology Delft. He has 10 patents filed and 5 issued, and will be one of the organizers of the technical program of PARTEC 2013 in Nuremberg, Germany.