Book excerpt: Biogenic Nanoparticles for Cancer Theranostics outlines the synthesis of biogenic nanoparticles to become cancer theranostic agents. The book also discusses their cellular interaction and uptake, pharmacokinetics, biodistribution, drug delivery efficiency, and other biological effects. Additionally, the book explores the mechanism of their penetration in cancerous tissue, its clearance, and its metabolism. Moreover, the in vitro and in vivo toxicological effects of biogenic nanoparticles are discussed. This book is an important reference source for materials scientists and biomedical scientists who are looking to increase their understanding of how biogenic nanoparticles are being used for a range of cancer treatment types. Metal nanoparticles have traditionally been synthesized by classical physico-chemical methods which have many drawbacks, such as high energy demand, high cost and potential ecotoxicity. As a result, the biosynthesis of metal nanoparticles is gaining increasing prominence. Biosynthesis approaches to metal nanoparticles are clean, safe, energy efficient and environment friendly. Explains the synthesis methods and applications of biogenic nanoparticles for cancer theranostics Outlines the distinctive features of biogenic nanoparticles that make them effective cancer treatment agents Assesses the major challenges of using biogenic nanoparticles on a mass scale