Characters in 2010: Odyssey Two

Dr. Heywood Floyd

American scientist and former space council chief who leads the American contingent aboard the Leonov.

Also in 2001: A Space Odyssey, A Rope-In Case, 2061

Dave Bowman

Discovery's former commander, whose fate beyond the monolith is one of the book's central mysteries.

Also in A Rope-In Case

Hal 9000

Discovery's onboard computer, whose malfunction doomed the first mission and whose revival is part of the new one.

Also in A Rope-In Case, 2061

Walter Curnow

Boisterous American engineer who knows Discovery's systems and works to make her spaceworthy again.

Dr. Chandra (Space Odyssey)

Self-effacing Indian computer scientist who built HAL and is tasked with reviving him.

Tanya Orlova

Stern, expert Soviet commander of the Leonov.