Fibrinogen is a crucial molecule in humans with an extraordinary role in stopping and preventing bleeding. Fibrin networks in robust clots protect against main causes of death in young age groups - maternal death due to peripartum haemorrhage (PPH) and exsanguination due to trauma-induced coagulopathy (TIC). Fibrinogen secures patient outcome during and after major surgical procedures in all age groups. This book compiles all relevant aspects concerning hypofibrinogenaemia and fibrinogen replacement. Internationally accepted experts contributed their expertise and knowledge to this book and made it a helpful tool in clinical practice. They highlight the pathophysiology of fibrinogen and its use in cardiac surgery, trauma bleeding, peripartum haemorrhage and paediatric patients and discuss the application of fibrinogen from different sources.