Mnemonics are strategies that can enhance learning and memory. The use of mnemonics dates back to the Ancient Greeks, but empirical research on mnemonics did not begin until the 1960s. At least ten categories of mnemonics have been identified, which has led to the creation of a classification framework. The various types of mnemonics include the method of loci, the pegword system, story mnemonics, link mnemonics, acronyms, acrostics, rhymes, the keyword method, figure alphabet, and yodai mnemonics. Beyond a summary of these categories, theoretical explanations are provided, and controversies in the research are discussed. Finally, a summary of research on mnemonics in action is provided in a variety of fields, including mathematics, language learning, health care, music, and psychology.