"Dragon Quest, published as Dragon Warrior in North America until 2005, is a series of internationally best-selling console role-playing game (RPG) titles created by Yūji Horii and his studio, Armor Project, and published by Enix. (currently Square-Enix after the merge in 2003). The series has significantly impacted the development of console RPGs, and introduced a number of features to the genre. Installments of the series have appeared on MSX computers, and the Nintendo Entertainment System (NES), Super Nintendo Entertainment System (SNES), Game Boy Color (GBC), Game Boy Advance (GBA), Nintendo DS, PlayStation (PS1), PlayStation 2 (PS2) and Wii video game consoles, and on several models of mobile phone. Nearly every game in the main series has been adapted to anime and manga. Each Dragon Quest video game soundtrack has been arranged into an orchestral piece; the series was the first to have a soundtrack performed by live orchestra.
For the majority of the series, Dragon Quest games were released under the title Dragon Warrior in North America to avoid trademark conflict with the role-playing game DragonQuest, which was published by Simulations Publications in the 1980s until the company's 1982 bankruptcy and acquisition by TSR, Inc.. TSR continued publishing the line as an alternative to Dungeons & Dragons (D&D) until 1987, and in 2003, Square Enix registered the Dragon Quest trademark in the United States.
The Dragon Quest series is known for its strong continuity, which has been contrasted to the Final Fantasy series. Common elements persist throughout the series and its spinoff titles: turn-based combat; recurring monsters, including Slime which has become the series' mascot; text-based menu systems until the English version of Dragon Quest VIII: Journey of the Cursed King; and, until Dragon Quest IX: Sentinels of the Starry Skies, random encounters in the main series. The series is also known for being one of the few long-running video game series to have a stable key development team.
None of the Dragon Quest titles were published outside of Japan or North America until the series made its European debut with Dragon Quest VIII: Journey of the Cursed King. As of February 2010, the Dragon Quest series has sold over 53 million units worldwide. It is Square Enix's second most successful franchise after Final Fantasy and is often cited as the most popular video game franchise in Japan."
Source: Wikipedia, "Dragon_Quest", available under the CC-BY-SA License.