This lecture covers the basics of filtration, regulatory aspects of virus safety in biopharmaceutical manufacturing, and the technology behind virus filtration. It discusses the importance of virus removal in biotech processes, the types of filtration methods, and the strategies for virus safety. The presentation also delves into the global regulatory guidelines for virus safety, the selection of relevant viruses for testing, and the criteria for virus selection. Additionally, it explores the impact of local vs. global regulatory guidelines, the role of bacteriophage testing, and the considerations for virus filter clearance studies.