The Gentleman's Magazine was the first general-interest magazine, and the most influential periodical of its time.
The Gentleman's Magazine was founded in London by Edward Cave in January, 1731. The orginal complete title was The Gentleman's Magazine: or, Trader's monthly intelligencer. Cave's innovation was to create a monthly digest of news and commentary on any topic the educated public might be interested in, from commodity prices to Latin poetry. It carried original content from a stable of regular contributors, as well as extensive quotes and extracts from other periodicals and books. Cave, who edited The Gentleman's Magazine under the pen name "Sylvanus Urban," was the first to use the term "magazine" (meaning "storehouse") for a periodical.
Prior to the founding of The Gentleman's Magazine, there had been specialized journals, but no such wide-ranging publication (though there had been attempts, such as The Gentleman's Journal, which was edited by Peter Motteux and ran from 1692 to 1694).
Samuel Johnson's first regular employment as a writer was with The Gentleman's Magazine. During a time when parliamentary reporting was banned, Johnson regularly contributed parliamentary reports as "Debates of the Senate of Magna Lilliputia." Though they reflected the positions of the participants, the words of the debates were mostly Johnson's own.
Cave, a skilled businessman, developed an extensive distribution system for The Gentleman's Magazine. It was read throughout the English-speaking world. It finally ceased publication in September, 1907.
An on-line archive of The Gentleman's Magazine from 1731-1750 can be found at the Bodleian Internet Library of Early Journals.