Ethers and crown ethers are important structural parts of many man-made or natural organic materials with medicinal, agrochemical or technological attributes. In recent years, extensive studies have been conducted for developing novel ether synthesis methods. This book summarizes recent advances in synthesizing dialkyl, alkyl aryl, diaryl, cyclic, and crown ethers. It also discusses their substantial applications in various fields such as organic synthesis, ionic liquids, protecting groups, photoswitchable catalysis, phase transfer catalysts, solvents, biological functionality, anticancer properties and antimicrobial effects, drug delivery, and biofuels. Providing an invaluable reference for undergraduates, postgraduates and researchers interested in organic chemistry, it also contributes to the literature for chemical researchers working in industry.