Most Popular Non-fiction Books of the 20th century

The History of Middle-earth #2

The Book of Lost Tales, Part Two

J. R. R. Tolkien, Christopher Tolkien

Fantasy · Middle-earth · Non-fiction

1984

The History of Middle-earth #12

The Peoples of Middle-earth

J. R. R. Tolkien, Christopher Tolkien

Fantasy · Middle-earth · Non-fiction

1996

The History of Middle-earth #5

The Lost Road and Other Writings

J. R. R. Tolkien, Christopher Tolkien

Fantasy · Middle-earth · Non-fiction

1987

The History of Middle-earth #4

The Shaping of Middle-earth

J. R. R. Tolkien, Christopher Tolkien

Fantasy · Middle-earth · Non-fiction

1986

The Letters of J. R. R. Tolkien

J. R. R. Tolkien, Christopher Tolkien, Humphrey Carpenter

Non-fiction

1981

The History of Middle-earth #8

The War of the Ring

J. R. R. Tolkien, Christopher Tolkien

Fantasy · Middle-earth · Non-fiction

1990

The History of Middle-earth #7

The Treason of Isengard

J. R. R. Tolkien, Christopher Tolkien

Fantasy · Middle-earth · Non-fiction

1989

The History of Middle-earth #1

The Book of Lost Tales, Part One

J. R. R. Tolkien, Christopher Tolkien

Fantasy · Middle-earth · Non-fiction

1983

The History of Middle-earth #6

The Return of the Shadow

J. R. R. Tolkien, Christopher Tolkien

Fantasy · Middle-earth · Non-fiction

1988

Supernatural Horror in Literature

H. P. Lovecraft

Non-fiction

1927

The History of Middle-earth #9

Sauron Defeated

J. R. R. Tolkien, Christopher Tolkien

Fantasy · Middle-earth · Non-fiction

1992

Trillion Year Spree: The History of Science Fiction

Brian Aldiss, David Wingrove

Hugo Award · Locus Award · Non-fiction

1988

Discworld Mapps

Death's Domain

Terry Pratchett, Paul Kidby, Stephen Briggs

Non-fiction

1999

Star Trek

The Trouble with Tribbles: The Birth, Sale and Final Production of One Episode

David Gerrold

Star Trek · Non-fiction

1973

Star Trek: The Original Series

Beam Me Up, Scotty

Peter David, James Doohan

Space Opera · Star Trek · Non-fiction

1996

A-Z of Tolkien

David Day

Middle-earth · Non-fiction

1993

The Saga of Pliocene Exile

A Pliocene Companion

Julian May

Non-fiction

1984

The Book of the New Sun

The Castle of the Otter

Gene Wolfe

Non-fiction

1982

Angels & Visitations

Neil Gaiman

Fantasy · Short Stories · Non-fiction

1993

Sojan

Michael Moorcock

Fantasy · Science Fiction · Sword and Sorcery · Short Stories · Non-fiction

1977

The Supernatural: Phenomena Beyond Belief

Rhiannon Lassiter

Non-fiction

1999

The Coming Global Superstorm

Whitley Strieber, Art Bell

Non-fiction

1999

Buffy the Vampire Slayer

The Monster Book

Christopher Golden, Thomas E. Sniegoski, Stephen R. Bissette

Non-fiction

1999

Buffy the Vampire Slayer

The Watcher's Guide

Christopher Golden, Nancy Holder

Non-fiction

1999

Buffy the Vampire Slayer

Sunnydale High Yearbook

Christopher Golden, Nancy Holder

Non-fiction

1999

Rockets, Redheads and Revolution

James P. Hogan

Science Fiction · Short Stories · Non-fiction

1999

Resurrecting The Mummy: The Making of the Movie

Pat Cadigan

Non-fiction

1999

Outlander

The Outlandish Companion

Diana Gabaldon

Non-fiction

1999

No Limits: Developing Scientific Literacy Using Science Fiction

Julie E. Czerneda

Anthology · Non-fiction

1999

Saucer Wisdom

Rudy Rucker

Science Fiction · Non-fiction

1999

Seek!

Rudy Rucker

Short Stories · Non-fiction

1999

The Seed of Lost Souls

Poppy Z. Brite

Horror · Non-fiction

1999

Borderlands of Science

Charles Sheffield

Non-fiction

1999

Discworld Mapps

A Tourist Guide to Lancre

Terry Pratchett, Stephen Briggs

Non-fiction

1998

Confirmation: The Hard Evidence of Aliens Among Us

Whitley Strieber

Non-fiction

1998

Good Faeries, Bad Faeries

Brian Froud

Non-fiction

1998