Occupations and respiratory disease intersect in three ways. First, and most familiar, are those instances where a workplace exposure has given rise, de novo, to a condition that would not otherwise have occurred a truly “occupational” disease. Second, exposures or other circumstances encountered at work may worsen a pre-existing condition – a common example is work-exacerbated asthma, covered in chapter 4 [1]. Third, a pre-existing disease may render a patient relatively or completely unfit to carry out their job. This last, more properly the domain of the occupational health specialist, is brought into sharp relief by an ageing workforce but is a matter also in some specialist areas such as commercial diving (covered in chapter 17 [2]) and work at altitude (chapter 18 [3]). The Monograph opens with a global perspective, a reminder that in a rapidly industrialising world the hazards of work are not only increasing but are too often unregulated and are responsible for literally countless cases of crippling disease (chapter 1) [4]. We then include a chapter that provides an overview on exposure assessment in the workplace (chapter 2) [5]. The chapters that follow cover the full spectrum of occupational respiratory diseases, including: those that are specific to work (such as silicosis in chapter 10 [6], coal worker’s pneumoconiosis in chapter 11 [7] and mesothelioma in chapter 9 [8]) those that can arise from work but are clinically indistinguishable from cases occurring otherwise (COPD in chapter 6 [9], lung cancer in chapter 16 [10] and, arguably, asbestosis in chapter 8 [11]) and those where a workplace aetiology can be determined on a case-by-case basis (occupational asthma in chapter 3 [12]). Finally, we include two chapters on “environmental” exposures. The first, concerned with “outdoor exposures”, includes the often ignored but surely important topic of environmental allergens (chapter 19) [13]. The second weaves a skilful path through the minefield of misconceptions that characterise the issue of “indoor” domestic exposures (chapter 20) [14]. Throughout, we have asked authors to cover the most recent advances in their subject. They have risen to the task with great skill and provided us with a stark reminder that this is a field that never stands still. Few, if any, predicted, for example, that two of the oldest occupational lung diseases would have shown a resurgence in what we had believed to be well-regulated societies. Chapter 10 covers the very recent epidemics of aggressive silicosis among stonemasons and kitchen fitters in countries such as Australia, Spain, Italy and Israel, attributable to the invention of “engineered” stone, a lethal material that could hardly be bettered as a vector for the disease [6]. The depressing return of progressive massive fibrosis in US coalminers, arising from the dysregulation of small mines in the Appalachians, is ably described in chapter 11 [7]. Unpredicted these may have been but unpredictable they were not. After all, we know enough about most occupational lung diseases to prevent them (almost) entirely but, collectively, we lack the will. We recognise that this Monograph has been written primarily from the perspective of a high-income country that is not to ignore the tremendous importance of occupational and environmental diseases in low- and middle-income countries, but much of the content here is generalisable to all settings. This Monograph was written, reviewed and edited during the height of the first wave of the COVID-19 pandemic. Most of its authors and reviewers were at the forefront of the clinical response and we are especially grateful for their grace and tireless effort in what we know were exhausting times. We thank, too, John R. Hurst (Editor in Chief), Rachel Gozzard (ERS Monograph Managing Editor) and Caroline Ashford-Bentley (ERS Editorial and x https://doi.org/10.1183/2312508X.10023620