Psychological contracts of safety are the beliefs of individuals about reciprocal safety obligations inferred from implicit or explicit promises. The literature on psychological contracts is growing but the existence of psychological contracts in relation to safety has not been established. This book documents the applicability of the psychological contract to occupational safety. A psychological contract of safety measure is developed and validated and a model of safety investigating breach and fulfilment of the psychological contract of safety is tested. Qualitative findings show employees do think and talk about safety in a contractual, reciprocal manner, demonstrating evidence for the construct. Quantitative findings indicate employer breach of obligations negatively influences safety climate attitudes, whilst employee fulfilment of obligations positively influences safety behaviour. Also, employee perceptions of the extent to which the employer fulfils safety obligations influences employee reciprocation of safety obligations, lending support to the assertion that positive organisational social exchange relationships has positive outcomes for occupational safety.