## 4 Discussion and Conclusions  
The paper proposed a systematic literature review aiming to understand the status of the digital building logbook in the AECO field. Sub-questions were defined to address different aspects of the problem and contribute to a more detailed analysis. For this purpose, the study explored current trends related to the use of digital building logbooks, carrying out a bibliometric and thematic analysis. It relied on the use of two scientific databases, Scopus and Web of Science, looking at the period from 2010 to 2024. The quantity of publications acquired remains limited with a total of 25 documents analyzed, indicating a shortage of thorough analyses of this tool. Nonetheless, there has been an increase in the number of publications over the years, with a peak in 2023. Most articles choose a methodological approach that uses case studies for the development of the authors' research, highlighting the main applications of the digital building logbook related to the use phase. Concerning the thematic analysis of the selected articles, the results on the data that are typically stored in a digital building logbook reveal that no standardized model exists for the building logbook, leading to variations in the data required across different countries. The literature review helped in outlining the categories of information required by logbook proposals and, consequently, in defining which are the main indicators that should be contained within the digital building logbook. The cluster of indicators, as suggested by the collected Horizon2020 logbook proposals, can describe the building and its technical characteristics, as well as the building material inventory. In addition, it can contain financial, legal, and insurance documents, the design and plans for the building, and the design and plans for building interventions. It can record data on the energy efficiency of the building, including energy consumption and certifications, and data from Internet of Things devices installed in the building to monitor systems like HVAC, lighting, and security. The European Commission has made great efforts in the creation and dissemination of this tool. On one hand, the literature review shows that several digital building logbooks have been developed within Horizon2020 European projects; on the other hand, the European Commission's study proposed a digital building logbook framework by identifying the most crucial points through the use of surveys in 2020. However, there is not an official version for implementing this tool within the field yet. The findings on the digital building logbook supporting the building's entire lifecycle outline its maturity in operations and end-of-life phases, while registering a sporadic use in construction and design phases. This analysis also answers how the digital building logbook impacts facility management. In fact, the digital building logbook facilitates long-term data management by reliably capturing and preserving all pertinent building data. They improve building longevity and performance by recording the history of operations and maintenance, which is essential to efficient facility management. This makes it possible for facility managers to optimize energy usage, implement predictive maintenance plans, and guarantee responsible resource management. By integrating the digital building logbook with digital twin models, building performance may be continuously tracked over time, and real-time feedback can be obtained to enhance decision making about maintenance schedules and building performance. Furthermore, the digital building logbook plays a critical role in building renovation processes by providing a centralized, digital repository of essential building information. The digital building logbook contains up-to-date information about the condition of building systems (e.g., HVAC, structure, and electrical systems), helping stakeholders assess what needs renovation.