Book excerpt: Organic Nanomaterials for Cancer Phototheranostics highlights the use of biocompatible building blocks to make nanomaterials that can aid in medical treatment through better diagnostic and antitumor efficacy. It synthesizes the current literature on synthetic strategies and designs based on peptides, proteins, polymers, lipids, and their conjugates, as well as composites and complexes with metals and inorganic components used to form the nanomaterials. Mechanistic approaches, clinical problems, and therapeutic and diagnostics mechanisms are covered in each chapter. Cellular interactions and uptake, pharmacokinetics, biodistribution, drug delivery efficiency, and safety concerns of these types of nanomaterials are discussed, as well. Other topics looked at include photostability, clearance, metabolism, in-vitro and in-vivo mechanisms, therapeutic efficacy, imaging, and toxicology. - Outlines fabrication and design strategies of peptides, proteins, polymers, lipids, composites, and complexes with metals and inorganic components - Discusses the limitations and challenges of organic nanomaterials in clinical use, including their mechanisms of penetration into cancer cells and tissue, photostability, clearance, and metabolism - Covers clinical problems and therapeutic and diagnostics mechanisms