Author-date system of referencing
The name of the author-date referencing system points to one of its distinguishing features. The name Harvard system suggests that Harvard University uses it; in fact it does not.
The author-date system is designed to interrupt a writer's words as little as possible, and aims to limit the information to two words in the first instance: the name of the author, and the date of publication of the source being cited. For more detail on how to put a reference in the text of your writing, see Author-date in your text.
The two words (the author's surname and the date of publication) point to a List of References at the end of the paper or book being written. The Reference List gives all the bibliographical information needed for the reader to track down the source being used, whether to check it or to find further information. For more detail, see Author-date list of references.
(The reason for preferring the name author-date system is that Harvard University (in the United States) does not use this system. See Harvard referencing for more.)