How many books are in the series the dragonriders of pern?

Answer 1

Original trilogyLater collected in an omnibus edition. These stories take place immediately before and during the Ninth Pass.

• Dragonflight (1968; composed in part of McCaffrey's first two Pern novellas, Weyr Search and Dragonrider, originally published in 1967)
• Dragonquest (1970)
• The White Dragon (1978; although published prior to Dragondrums, The White Dragon continues the adventures of certain Dragondrums characters; McCaffrey recommends reading Dragonsong, Dragonsinger and Dragondrums before The White Dragon; The White Dragon incorporates McCaffrey's story "A Time When")

Harper Hall trilogyLater collected in an omnibus edition. These stories take place immediately prior to and concurrently with those depicted in Dragonquest and The White Dragon.

• Dragonsong (1976)
• Dragonsinger (1977)
• Dragondrums (1979)

Other novels and anthologies

• Moreta: Dragonlady of Pern (1983; both this and Nerilka's Story are set at the end of the Sixth Pass, centuries before the events in Dragonflight)
• Nerilka's Story (1986)
• Dragonsdawn (1988; first in chronological order, depicts the colonization of Pern, the First Fall of Thread, the creation of the dragons, and the colonists' move north.)
• "The Impression" (1989; short story included in The Dragonlover's Guide to Pern)
• The Renegades of Pern (1989)
• All the Weyrs of Pern (1991)
• The Chronicles of Pern: First Fall (1993, anthology set mostly after Dragonsdawn)
  • "The Survey: P.E.R.N." (originally published in 1993 as "The P.E.R.N. Survey")
  • "The Dolphins' Bell" (originally published in 1993)
  • "The Ford of Red Hanrahan"
  • "The Second Weyr"
  • "Rescue Run" (originally published in 1992)
• The Dolphins of Pern (1994)
• Red Star Rising (1997) (called Dragonseye for U.S. release; set at the beginning of the Second Pass)
• The Masterharper of Pern (1998; prequel to Dragonflight and the other works of the Ninth Pass)
• The Skies of Pern (2001)
• A Gift of Dragons (2002 anthology collecting previously published stories and a new story)
  • "The Smallest Dragonboy" (1973; short story previously collected in Get Off the Unicorn)
  • "The Girl Who Heard Dragons" (1986; short story collected in both The Girl Who Heard Dragons and A Gift of Dragons)
  • "Runner of Pern" (1998 novella set, like Masterharper of Pern, some time before the events of Dragonflight; collected in Legends and A Gift of Dragons)
  • "Ever the Twain" (2002 short story original to A Gift of Dragons; time period unclear)
• "Beyond Between" (2003 short story in Legends II: Short Novels By the Masters of Modern Fantasy, Robert Silverberg, ed.; set after the events of Moreta)

Books written with/by Todd McCaffrey

• Dragon's Kin (2003, with Todd McCaffrey; set prior to the Third Pass)
• Dragonsblood (2005, written by Todd McCaffrey; primarily set several years after Dragon's Kin)
• Dragon's Fire (2006, with Todd McCaffrey)
• Dragon Harper (December 2007, with Todd McCaffrey)
• Dragonheart (November 2008, written by Todd McCaffrey)

Future Books

• Working Title: After the Fall (is Over) or New Era Pern
• Dragongirl (Sequel to Dragonheart, written by Todd McCaffrey)[1]
• "Dragonrider" (Sequel to Dragongirl, written with Todd McCaffrey)
• Dragon's Time" (Sequel to Dragonrider, written with Todd McCaffrey)
• Dragon's Night (Co-written by Todd and Anne McCaffrey, To be released 28 Dec. 2010)[2]

Gamebooks and companion books

• Dragonharper (1987, gamebook written by Jody Lynn Nye)
• Dragonfire (1988, gamebook written by Jody Lynn Nye)
• The Atlas of Pern by Karen Wynn Fonstad is a collection maps based upon places mentioned in Pern.
• People of Pern by Robin Wood and Anne McCaffrey is a collection of portraits of the people of Pern.
• The Dragonlover's Guide to Pern by Jody Lynn Nye and Anne McCaffrey contains the short story "The Impression" as well as numerous charts and extra information about Pern.

Answer 2

There are 24 books in the Dragonriders of Pern series by Anne McCaffrey.