The World Health Organization estimates that about 2.9 billion workers around the world are regularly exposed to risks at their workplace. Therefore, a significant fraction of the world's working force, principally in low- and middle-income countries, is at an increased risk of occupational hazards with direct implications on occupational safety and health. Occupational injuries and illness lead to (short/long) workers' absences with significant economic costs for both employees and employers. Also, the quality of life and wellbeing of active workers are profoundly affected. This book - An Essential Guide to Occupational Exposure - will attract the attention of people that want to know more about occupational exposure and its implications on hygiene, safety, and health in work environments. This work aims to highlight the predominant occupational risks that all working groups can be exposed to. Also, it informs readers about emerging health surveillance tools, namely cytogenetic and human biomonitoring assays, that are being used in the assessment of occupational exposure and health risk assessment. This book is aimed at the active and working civil society, occupational safety and hygiene technicians among other related occupations (e.g., health professionals), scientific community, and stakeholders. This reading will promote a reflection on the topic of occupational exposure and its implications on the safety and health of workers from different occupations.