Plastics are making their way into ever new application areas. The continuous growth rates confirm this. In particular, the targeted modification of plastics and recycling are becoming increasingly important. Through the deliberate modification with additives, the property profiles of the compounds can be tailored more precisely to the needs of users. At the same time, the industry demands ever higher quality and a process-oriented mindset. This makes it essential to monitor the core process in plastic processing using suitable technologies. Inline measurement technology is the method that most directly determines process parameters and provides real-time feedback. This will be a guarantee for optimal process control as well as efficient and economical compounding in the future. This book offers the first overview.