Dr. Marek Maciejewski reported in 1999 in an excellent work the second part of a series of papers dealing with the results of the International Confederation for Thermal Analysis and Calorimetry (ICTAC) Kinetic Analysis Project [M.E. Brown, M. Maciejewski, S. Vyazovkin, R. Nomen, J. Sempere, A. Burnham, J. Opfermann, R. Strey, H.L. Anderson, A. Kemmler, R. Keuleers, J. Janssens, H.O. Desseyn, C.-R. Li, T.B. Tang, B. Roduit, J. Malek, T. Mitsuhashi, Thennochim. Acta 355 (2000) 125-143; M. Maciejewski, Thermochim. Acta 355 (2000) 145-154; S. Vyazovkin, Thermochim. Acta 355 (2000) 155-163; A.K. Burnham, Thennochim. Acta 355 (2000) 165-170; B. Roduit, Thermochim. Acta 355 (2000) 171-180]. In this work Dr. Maciejewski emphasized the very limited applicability of the kinetic methods that use single-heating rate data and stated that to obtain reliable kinetic descriptions, computational methods that employ multi-heating rate data should be used for treating multistep processes. The reasons supporting this argument are presented in his "Fact 2", where it was stated that two different models represent very similar alpha-T curves at one heating rate (5 degrees C/min), but at other two different heating rates (2 and 10 degrees'C/min) the same kinetic parameters used at 5 degrees C/min illustrate very different curves. In this letter to the editor, we show different examples where we intend to illustrate that interactions among parameters are even higher than this author described, since there is a possibility that different models, could be able to reproduce the same conversion curves at different heating rates simultaneously. (c) 2006 Elsevier B.V. All rights reserved.