It is already a generally accepted opinion today that the course of DTA, DSC and TG curves is deteriorated by the non-isothermal heating control and by other experimental conditions to such an extent that it is more characteristic for the experimental conditions, than for the transformation itself. This problem can be eliminated completely by the simultaneous use of "transformation-governed heating control" (TGHC) and "self-generated atmosphere" (SGA) ensuring quasi-isothermal, quasi-isobaric conditions for the DTA measuring technique (Q-DTA). This experience is proven on the examples of the evaporation of water under boiling, the dehydration of Ca(OH)(2), CuO(4)(.)5H(2)O, CaBr(2)(.)6H(2)O, Mg(OH)(2) and CaSO(4)(.)2H(2)O by providing both, the results obtained by the DTA, TG and the Q-DTA measuring techniques. (C) 2004 Elsevier B.V. All rights reserved.