Book excerpt: The book comprehensively introduces readers to various aspects of flavonoids, a category of natural metabolites that exhibits various pharmacological effects. It discusses their chemistry, absorption and metabolism, mechanisms of action and toxicology as well as future perspectives for clinical applications, and also provides detailed insights into their anti-cancer properties, since flavonoids are known to modulate tumor-associated intracellular as well as extracellular signaling pathways. The book also highlights the current research on the health effects of selected flavonoids, and their various roles in cancer prevention and treatment. Lastly, the book elucidates nanotechnology-mediated tools to enhance the bioavailability and solubility of flavonoids to improve their bioactivity and pharmacokinetic parameters.