This paper presents an extensive literature review on the field of condition-based
maintenance (CBM). The paper encompasses over 4000 contributions, analysed through bibliometric
indicators and meta-analysis techniques. The review adopts Factor Analysis as a dimensionality
reduction, concerning the metric of the co-citations of the papers. Four main research areas have been
identified, able to delineate the research field synthetically, from theoretical foundations of CBM;
(i) towards more specific implementation strategies (ii) and then specifically focusing on operational
aspects related to (iii) inspection and replacement and (iv) prognosis. The data-driven bibliometric
results have been combined with an interpretative research to extract both core and detailed concepts
related to CBM. This combined analysis allows a critical reflection on the field and the extraction of
potential future research directions
