The problem domain of the investigation presented in this dissertation is knowledge increase. In particular the research is concerned with the process of knowledge increase. The research problem formulated is formulated a posteriori: "Which factors determine the increase of personal knowledge that occurs by absorbing a particular new knowledge of an individual, who is a member of an organization, and how these factors work?" To explore and shed light on this problem a number of disciplinary boundaries were engaged and some models, tools, descriptions, etc. were borrowed from a number of related disciplines. These areas are briefly presented in the dissertation, restricting presentation to the relevant issues. There are three models developed for this thesis and they are subsequently integrated into a fourth model. First the 'Model of Learning Willingness' (MLW) is developed to consider personal and organizational value systems. For this model, new concepts have been created, to indicate the position of new knowledge in both personal and organizational value systems. Stable and the unstable states of the model are identified as well as how it is possible to pass from one state to another as result of an interaction between the two value systems by means of influencing each other. Applying a 'systems theory approach' on the cognitive psychology conception of knowledge, the impact of the characteristics of existing knowledge on the absorption of new knowledge is described. The developed model is called the 'Model of Learning Capability' (MLC). - This is the second model. It is also necessary to pay attention to the ability to acquire new knowledge; this is described by the 'Model of Attention' (MA) - the third model. This model is based on two main factors, namely cognitive and social conditions. These three models are thus integrated into fourth one, which is called the 'Model of Learning Ability' (MLA). For exploration/validation the model is wwwed with the Doctus Knowledge-Based Expert System, which was also the means of comparing the evolved hypotheses with the input from reality, namely observations and thought experiments. The first insight from the model is a better understanding of the process of 'knowledge increase'. The model can also be used to support choosing the right person to learn a particular piece of new knowledge, to identify the reason for someone not performing well with regards to learning and/or identifying a possible way of improving the process. Using the logic of the model experts can also be evaluated in the process of knowledge acquisition when building an expert system. Considering the achieved results some new problems emerge: It is not known what motivates the personal value system during the knowledge absorption; it is not known if the model can be extended to other forms of knowledge increase besides learning; it is not known how the social factors apart from love (i.e. power and money) affect the attention. Some new research ideas also evolved from this investigation, e.g. an attempt to model the knowledge using dimensions of understanding.