A sub-series of science fiction novels taking place in the Commonwealth Universe by Peter F Hamilton.

An overarching science-fiction series by Peter F Hamilton.

A short run series published by Target Books featuring solo adventures of people who were once companions of the Doctor in Doctor Who.

A science fiction series by C J Cherryh.

A series of books about Conan the Cimmerian written by Robert E Howard, L Sprague de Camp and Lin Carter.  This is the core series of books which are all from or based on stories or notes by Robert E Howard.

The seven book Conan series written by Robert Jordan.

Series of fantasy novels by Raymond E Feist.  A subset of the Riftwar Cycle.

A trilogy of science fiction novels by Timothy Zahn.

Star Wars universe series set 18 ABY.

A Crime Mystery series written by J K Rowling under the pseudonym Robert Galbraith.

ACOTAR - A fantasy series by Sarah J Maas

A series by Kate Elliot.

A trilogy of fantasy novels by David Drake.  A subseries in the Lord of the Isles series.

A loosly related series of science fiction books that all take place in the same universe.  Written by Iain M Banks.

A series of children's books featuring the monkey Curious George.

A series of fanrtasy novels by Edward W Robertson.

A series of books written by C J Cherryh that takes place in the Alliance-Union Universe.  This trilogy was originally issued as one hardback volume entitled Cyteen.

A series of books by Brian M Stableford originally published by Daw Books.

A fantasy series by Elliot Brooks.

A series of fantasy/horror books written by Stephen King over a period of years.  The series is based on the poem "Childe Roland to the Dark Tower Came" by Robert Browning.

A series of science-fantasy novels and short stories by Marion Zimmer Bradley

Series of fantasy novels by Raymond E Feist.  A subset of the Riftwar Cycle.

A series within the Tortall universe.

A series of chidlren's books by David Shannon.

A series of science fiction novels by Philip José Farmer.

A universe created by Christopher Stasheff which encompasses several series including the Warlock of Gramarye and stories.  DDT stands for Decentralized Democratic Tribunal.

A series by Dean R Koontz that takes place in the same Frankenstein universe as Mary Shelley's.

A science fiction series by John Morressy

The first of the Dray Prescot series.

Series of fantasy novels by Raymond E Feist.  A subset of the Riftwar Cycle.

A series of science fiction novels by A Bertrand Chandler.  These are set within the Rim Worlds series.

Derrick Storm is a series of books written by Richard Castle as seen on the Castle television series.  It is unclear at this time if Tom Straw also wrote these books or not.

An encompasing series of several trilogies about the Deryni by Katherine Kurtz.

Two novels starring mostly the same cast but in alternate realities.

A series of novels by Jeff Lindsay about a serial killer that you inexplicable route for.

A science fiction series by Jo Clayton

A series of science fiction/fantasy novels by Sharon Green.

A science fiction, dark humor series by Douglas Adams

A series of humorous fantasy novels by Terry Pratchett.

A series of novellas by John Scalzi.

A dystopian science fiction series written for teens and young adults.

A series of pulp fiction from the 30s on.

A series of books featuring the 8th Doctor from the once popular British television show Doctor Who.

A series of anthology books featuring short stories with the Doctor from the BBC television series Doctor Who.

A series of non-fiction for children using Doctor Who as a vehicle.

This was a series of books about the television show Doctor Who featuring information on each of the first seven doctor in each volume.