Javier Grillo-Marxuach (pronounced HA-vee-air GREE-yoh MARX-watch) was a writer/producer on Lost through Season 2.
Prior to his work on Lost, Grillo-Marxuach wrote for a number of series including Charmed and Law and Order: Special Victims Unit. He was the creator and Executive Producer of ABC Family's The Middleman, based on his comic book series.
Grillo-Marxuach served as a supervising producer and writer on the first two seasons. Grillo-Marxuach left the Lost crew after the second season but continued to work as a "voice for hire" on The Lost Experience as the voice of DJ Dan.  He also attended the fan event "Lost Weekend" in 2009 and 2010.
Grillo-Marxuach wrote the following episodes of Lost:
- "House of the Rising Sun"
- "All the Best Cowboys Have Daddy Issues"
- "Hearts and Minds" (with Carlton Cuse)
- "...In Translation" (with Leonard Dick)
- "Born to Run" (story)
- "Orientation" (with Craig Wright)
- "Collision" (with Leonard Dick)
Grillo-Marxuach has noted that he was the writer who created the blast door map.
- Lost: The Complete First Season (DVD)
- Lost: The Complete Second Season (DVD)
- In Grillo-Marxuach's self-produced show Ask Javi, you can ask him any question and he will try to answer it. However, as a question that everyone kept asking was "What is the Monster?", he finally addressed this as best as he could.
- He created and writes The Middleman for Viper Comics. The Middleman was picked up by ABC Family in 2008 for a television series based on the comic.
- Attended high school in Ann Arbor, Michigan, home of the University of Michigan.
- Suggested in his July 9th Ask Javi podcast that Damon Lindelof is Speaker from The Lost Experience.
- Offers a forum for players of The Lost Experience to post their opinions and questions (answered as he sees fit) on his LiveJournal.
- States through the Notes from the Experience LiveJournal that he is not Speaker (although he is taking over Speaker's former blog), but he has "been known to essay the role of a certain donut-lovin' deejay on occasion."
- Grillo-Marxuach in The Evil Puppet Masters
- Personal site
- Ask Javi archives (look for what is the monster?)
- Notes from the Experience LiveJournal
- MarxWatch: Javi fan site
- Official ABC Family "Middleman" Site
- The Middleblog: The official "Middleman" production blog run by Javi