Plastic is a material that contains an organic substance of large molecular weight as an essential ingredient. Microplastics are the tiny plastic particles that are produced during commercial product development and from breakdown of larger plastics. The increasing concentration of plastics and microplastics in various ecosystems is a major environmental concern across the globe. Microplastics are classified into primary microplastics and secondary microplastics. The plastic fragments or particles that are less than or equal to 5.0 mm before they enter the environment are called primary microplastics, such as microfibers and microbeads. Environmental factors such as ocean waves and sun’s radiation lead to the breakdown of larger plastic items, such as water bottles, into smaller parts which are called secondary microplastics. A major disadvantage of microplastics and plastics is their inability to break up into smaller particles. Several studies have suggested that the exposure to microplastics in humans can potentially cause toxicity through oxidative stress. This book covers in detail various topics related to plastics and microplastics in the environment as well as their measurement, health risks and management