Sierra Six - Mark Greaney

Sierra Six

By Mark Greaney

  • Release Date: 2022-02-15
  • Genre: Mysteries & Thrillers
Score: 4.5
From 2,737 Ratings


It's been years since the Gray Man's first mission, but the trouble's just getting started in the latest entry in the #1 New York Times bestselling series.

Before he was the Gray Man, Court Gentry was Sierra Six, the junior member of a CIA action team.
In their first mission they took out a terrorist leader, at a terrible price. Years have passed. The Gray Man is on a simple mission when he sees a ghost: the long-dead terrorist, but he's remarkably energetic for a dead man. 
A decade of time hasn't changed the Gray Man. He isn't one to leave a job unfinished or a blood debt unpaid.


  • Sierra Six Review

    By dwill20498
    An amazing story - in fact two stories in one. The back and forth between two storylines was impressive. It was something new and special for the series. I thoroughly enjoyed this.
  • HUA

    By Julie Jas
  • This one I just read.

    By Runyon B
    Cool shades of gray. Just the way Mark likes that Color in between the typed lines. He has away and I'm looking for the next one he writes for the man in Court.
  • Six

    By Jefe68
    This is one of the best, if not the best, in the series.
  • Great book

    By grutfd
    Intense and exciting
  • Great Book

    By kmeyer430
    Loved every chapter. Was Hard to stop reading!
  • Gray Man’s Best

    By IBMCP
    I love the Gray Man series. I believe this was the best in the series so far. I couldn’t put it down. A real page turner.
  • Sierra Six. Mark Greaney

    By Wet again
    Another magnificent read in this series!! A terrorist presumed dead has resurfaced. His primary goal is to remove the Americans from the Middle East by detonating radioactive bombs on military facilities and other key areas. Non stop action. My highest recommendation!
  • Sierra Six

    By Edmdwp
    Mark Greaney has been waiting to write this book for a long time. Best book i’ve read all summer. Thanks
  • Greyman

    By jprice6
    Very good book,like the other books with the greyman