Short answers, pulled from the story.
Dungeon magazine was first published by TSR, Inc. in 1986 as a bimonthly periodical under the full title Dungeon: Adventures for TSR Role-Playing Games. The premiere issue was undated, but the cover of the second issue read "November/December 1986".
Dungeon ceased print publication in September 2007 with Issue 150. Wizards of the Coast announced the end of print publication on the 18th of April 2007, and transitioned the magazine to an online-only format.
Dungeon was published by TSR, Inc. from its founding in 1986, then passed to Wizards of the Coast in 1997 following TSR's financial difficulties. Paizo Publishing held the publishing rights from late 2002 until September 2007, after which Wizards of the Coast brought the magazine back as an online publication.
Adventure Paths were episodic, multi-part campaigns published in Dungeon beginning in 2003, designed to carry player characters from 1st level through epic levels (20th and above). By April 2013, four Adventure Paths had been completed: Shackled City, Age of Worms, Savage Tide, and Scales of War.
Dungeon won Origins Awards for Best Professional Adventure Gaming Magazine in 1990 and 1991. It also won multiple ENnie Awards in 2002, 2005, 2006, and 2007, including Best Adventure, Best Cartography, Best Aid or Accessory, and Best Campaign Setting for the Shackled City Adventure Path.
The final issue of Dungeon magazine was Issue 221, released in December 2013. Both Dungeon and its sister publication Dragon went on hiatus at the end of 2013 pending the release of the Dungeons and Dragons 5th edition. A successor publication called Dragon+ launched online on the 30th of April 2015.