The Paper presents theoretical and empirical findings about inventive activity. Major invention process models are considered, their comparative analysis is carried out, and their advantages and limitations are revealed. The least studied first stages of inventive activity were theoretically identified and became the main objective of this study. To specify the content of the first stages of the inventive process, an empirical study was carried out through the methods of peer review, written and oral surveys, content analysis and modelling. The study involved 15 experts, namely inventors with a significant number of patents. Based on the survey of experts and the analysis of other authors' investigations, the content of the first stages of inventive activity was specified and conclusions were drawn about their variability as well as the possibilities to apply them in developing inventive abilities and enhancing technical innovation processes. © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (https://creativecommons.org/licenses/by/4.0/).