The main aim of the monograph is to conceptualise the construct of business ecosystem identity. Its achievement required that the concept of organisational identity be included in the context of a specific network, such as the business ecosystem. More specific aims are as follows: to conceptualize organizational identity construct, as well as, network identity and business ecosystem; to form business ecosystem identity construct; to find if there is any opportunity for its operationalization and to investigate potential methods and tools for its future analysis. Facing the complexity of the proposed construct of the business ecosystem identity, the main research problem deals with explaining whether the construct of business ecosystem identity is valuable in the context of filling the research gap over the dynamics and survival of the business ecosystem. Research questions are as follows: 1) what is business ecosystem identity?, 2) what epistemological perspective should be adopted with reference to the proposed construct?, 3) what level of analysis is appropriate for its analysis?, and finally, 4) which research categories can be used to conceptualize the construct of business ecosystem identity? To find answers to the research questions relating to the main aim of the whole monograph the ontological bases and epistemological foundations of organizational identity (Chapter 1), business ecosystems (Chapter 2) and network identity (Chapter 3) needed to be reviewed. Specific properties of these constructs were generated and, above all, the characteristics of an ecosystem: re-emergence, self-organisation, co-adaptation, and co-evolution, were specified (Chapter 2). Measurable identity-related research categories, influencing business ecosystem survival, were identified (Chapter 3). It was assumed that the construct of business ecosystem identity (BEI) could be described and explored with the use of research categories such as: the identity strength, organizational/network identification, identity dualism, and ecosystem survival. Further, the conceptual approach to business ecosystem identity was the issue to validation adopting exemplification research throughout an illustrative case study (Chapter 4). The conducted research enabled methodological specification of the exploration of BEI, that is 1) data sources, 2) research methods, 3) object of research, namely a business ecosystem, and 4) research categories of business ecosystem identity and tools for their analysis. The form of explanatory reasoning was abduction (after: [Peirce 1903/1955; Reichertz 2007]), leading to predictions [Peirce 1997], presuppositions, which can be tested further [Urbański 2009; Ciesielski 2014; 2015]. As an effect of the conducted qualitative research, presuppositions were finally made as a starting point for further research: P1': A strong identity of the leader is determined by the perception of a hybrid business ecosystem identity. P2': The perception of the hybrid business ecosystem identity contributes to a strong identification with the business ecosystem. P3': A low assessment of the power of the leader's identity contributes to the lack of the utilitarian BE identity. P4': A low assessment of the power of business ecosystem identity contributes to the lack of the utilitarian BE identity. P5': There are strong relations between the power of business ecosystem identity and its leader(s). P6': The power of business ecosystem identity determines the survival of the whole ecosystem. P7': A stronger identity of leaders contributes to the increased chances of ecosystem survival. P8': A stronger identification with the business ecosystem contributes to the increased chances of its survival. The methodological framework was adopted to the convention of the qualitative approach, focusing on conceptual thinking and theory building rather than on hypotheses testing (e.g. [Bartunek, Rynes, Ireland 2006]). The presented qualitative approach is interpretative one and consists of a heterogeneous set of complementary approaches [Smith 2015; Gehman et al. 2017], having regard to the criteria for pursuing methodological rigor in interpretative research [Czakon (ed.) 2015, pp. 95-99]. The greatest epistemological contribution of the conducted studies is the conceptualisation of business ecosystem identity as a construct 1) allowing for the dynamics of identity and business ecosystem, and 2) using measureable research categories. The BEI construct should be considered significant for future theoretical and empirical research since it 3) enables the exploration of the business ecosystem survival mechanisms, which was empirically inaccessible before, and 4) explication of the business ecosystem boundaries, which are considered incomprehensible. BEI also opens a path to the research on 5) the direction of the relations of the proposed research categories and 6) the power of their significance from the viewpoint of co-adaptation, re-emergence, co-evolution, and self-organisation. The conceptualisation of business ecosystem identity provides room for extensive analysis of the categories of its survival, dynamics, and development mechanisms. A real challenge for the development of the researched concept seems to be the macro level of the analysis - the ecosystem network.(original abstract)