Managing organizations in the contemporary world seems to be more art nowadays than a process based on scientific grounds. Among other things this happens because many definitions of concepts, models and procedures on behaviour established in business as exemplary, unfortunately become outdated very soon and many of them are not efficient at all against accepted expectations. Changeability and unpredictability of situations in an organization make it complex, and managers, in spite of their better and better qualifications, as well as various competences, still cannot feel comfortable. They do not know how to efficiently motivate people to work, how to solve conflicts, and how to choose an optimal management style. The source of inefficient knowledge is the above mentioned changeability and turbulence of surrounding elements, organization variability and its system-like character. Due to the fact, that the area of human resources management brings most trouble for managers, it seems to be expedient to undertake further research in this scope. The authors of the monograph focused their attention on the analysis of a complicated problem connected with groups and teams functioning in an organization. They have made meticulous review of both concepts definitions; there was no unanimity among researchers in the scope of making difference in their essence. However, they have noticed many differences, which undoubtedly enrich knowledge in this subject. Important issue that was paid attention to at work is a problem of managing team in an organization. The authors often mention the advantage of team work over individual, especially in the context of gained synergic effect. It is, however, worth remembering that individualization of an approach to human resources management in an organization demands the necessity of noticing the fact that not every employee has predisposition and will to work in a team, similarly as not every manager can build and manage the team. Anyway one conclusion could be made that actually there is no an ideal style of management. Everything depends on what kind of employees' supervisor faces, what kind of features he owns himself and what preferences he has towards organization. Much is also depended on a type of organization culture established in a given organization, which mainly determines the way of people's work in an organization and its teams. The results of the authors' research present a lot of important aspects of the issue. An up-to-date problem taken into consideration is also a matter of gender equality. The authors' remarks confirm the thesis that there are no significant differences in managing styles for women and men; it is only a deeply rooted thinking in many people's minds. The monograph makes up a rich compendium of knowledge about the role and meaning of groups and teams in an organization and contributes a lot to systematizing discussed issues. It may serve as an important source of information for both theoreticians and practitioners of managing.