Question: What English author is known for a long series of novels that first started in 1971 and ended in 2015, where a portion of the novels focus on witches?

Context articles: Karen E. Taylor
A Certain Magical Index
Sara Ware Bassett
Inheritance Cycle
Nantucket series
Dayworld (trilogy)
Witches (Discworld)
Terry Pratchett
Garrett P.I.
De svarta riddarna

Karen E. Taylor is the author of "The Vampire Legacy" Series of novels, published by Kensington Books.
 A voracious reader of vampire/horror novels, Karen first started writing "Blood Secrets" in January, 1988.
 She conceived of writing the novel while living across the street from a very large cemetery.
 It was never intended to be the first book of an ongoing series, but fans who had read the novel demanded a sequel.
 To date, the series stands at seven titles, and has earned a cult following.
 Her short stories have appeared in numerous anthologies, including: "Love Bites", "100 Vicious Little Vampires", "100 Wicked Little Witches", "A Horror Story A Day", and "Seductive Spectres".
 In 2001, she was nominated for the Bram Stoker Award for best short story for "Mexican Moon".
A Certain Magical Index (とある魔術の<ruby ><rb>禁書目録</rb><rp> (</rp><rt >インデックス</rt><rp>)</rp></ruby> , Toaru Majutsu no Indekkusu ) is a Japanese light novel series written by Kazuma Kamachi and illustrated by Kiyotaka Haimura, which has been published by ASCII Media Works under their Dengeki Bunko imprint since April 2004.
 The plot is set in a world where supernatural abilities exist.
 The light novels focus on Tōma Kamijō, a young high school student in Academy City who has an unusual ability, as he encounters an English nun named Index.
 His ability and relationship with Index proves dangerous to other magicians and espers who want to discover the secrets behind him, Index as well as the city.
 Yen Press have licensed the novels in North America.
 A manga adaptation by Chuya Kogino began serialization in "Monthly Shōnen Gangan" from May 2007.
 J.C.Staff produced two 24-episode anime series between 2008 and 2011.
 An animated film was released in February 2013.
 The anime adaptations are licensed in North America by Funimation.
Sara Ware Bassett (1872 – 1968) was an American author of fiction and nonfiction.
 Her novels primarily deal with New England characters, and most of them are set in two fictional Cape Cod villages she created, Belleport and Wilton.
 Her first novel, "Mrs. Christy's Bridge Party", was published in 1907.
 She subsequently wrote more than 40 additional novels, continuing to write and publish into the late 1950s.
 Many of her novels focus on love stories and humorously eccentric characters.
 A number of her works are available as free e-books.
The Inheritance Cycle is a young adult tetralogy of high fantasy novels written by American author Christopher Paolini.
 Set in the fictional world of Alagaësia ( ), the novels focus on the adventures of a teenage boy named Eragon and his dragon, Saphira, as they struggle to overthrow the evil king Galbatorix.
 The series was originally intended to be a trilogy (named the "Inheritance Trilogy") until Paolini announced on October 30, 2007, while working on the third novel, that he believed the story was too complex to conclude in just three books.
The Nantucket series (also known as the Nantucket trilogy or the Islander trilogy) is a set of alternate history novels written by S. M. Stirling.
 The novels focus on the island of Nantucket in Massachusetts which was transported back in time to 1250 BC due to something called "The Event".
 Shortly thereafter a conflict develops between the democratic Republic of Nantucket and a group of renegade Americans led by the ex-Coast Guard lieutenant William Walker.
 The series was nominated for the Sidewise Award for Alternate History in 2000.
 The series is closely related to Stirling's Emberverse with "The Change" being the synonymous point of departure.
Dayworld is a trilogy of science fiction novels by Philip José Farmer, inspired by his own acclaimed short story "The Sliced-Crosswise Only-On-Tuesday World".
 They are set in a dystopian future in which people are allowed to live only one day of the week.
 For the rest of the six days they are 'stoned,' a kind of suspended animation.
 The novels focus on a man, Jeff Caird, who is a daybreaker: someone who lives more than one day a week.
 As the series progresses, the main character seems to be suffering from Dissociative Identity Disorder.
 The novels comprising the trilogy are:
A major subset of the "Discworld" novels of Terry Pratchett involves the witches of Lancre.
 They are closely based on witches in British folklore and a slightly tongue-in-cheek reinterpretation of the Triple Goddess.
Sir Terence David John Pratchett, OBE (28 April 1948 – 12 March 2015), better known as Terry Pratchett, was an English author of fantasy novels, especially comical works.
 He is best known for his Discworld series of 41 novels.
 Pratchett's first novel, "The Carpet People", was published in 1971.
 The first Discworld novel, "The Colour of Magic", was published in 1983, after which he wrote two books a year on average.
 His 2011 Discworld novel "Snuff" was at the time of its release the third-fastest-selling hardback adult-readership novel since records began in the UK, selling 55,000 copies in the first three days.
 His final Discworld novel, "The Shepherd's Crown", was published in August 2015, five months after his death.
Garrett P.I. is a series of books by the author Glen Cook about Garrett, a freelance private investigator.
 The novels are written in a film noir-esque style, containing elements of traditional mystery and detective fiction, as well as plenty of dialogue-based humor.
 The Garrett P.I. novels are set in a fantasy universe; the protagonist Garrett, during his adventures throughout his home city of TunFaire and across Karenta and the Cantard, meets elves, vampires, centaurs, trolls, gods, wizards, witches and more.
 Unlike most fantasy series, the Garrett P.I. novels focus more on the detective aspects of the story and less on the fantastic and magical aspects.
De svarta riddarna in Swedish or De svarte ridderne in Norwegian (in English "The Black Knights"; This series of novels has not been translated to English) is a 12-volume series of fantasy novels by Norwegian-Swedish author Margit Sandemo.
 It is the fourth of her long series of novels.
 The series begins when a 24-year-old man named Morten Andersen gets hurt badly and goes to the hospital.
 He expresses to his friend Unni his doubts that the accident he was in was not predestined and that he will die at his 25th birthday because of the curse which has been passed in his family.