Marine and freshwater biotoxins are a well-known problem in food safety, mainly for filter-feeding mollusks and for freshwater aquaculture. This is a challenging matter since, in recent years, toxic algal blooms seems to grow in frequency and duration, leading to longer closure of harvesting areas, disruption in trade, mortality in farmed fish and a growing concern in producers, consumers and health authorities. Unfortunately, in recent years toxins from far latitudes are emerging, leading to new human health problems. Research and exhaustive knowledge of a problem makes it easier to draw a scenario where the best management strategies are gathered. This book combines all if the information related to food-borne illness associated with marine or freshwater biotoxins, the anthropogenic and environmental factors that cause the appearance of toxic episodes and all available analytical procedures for phycotoxins detection.