Deism, the religious attitude typical of the Enlightenment, especially in France and England, holds that the only way the existence of God can be proven is to combine the application of reason with observation of the world.
 A Deist is defined as "One who believes in the existence of a God or Supreme Being but denies revealed religion, basing his belief on the light of nature and reason."
 Deism was often synonymous with so-called natural religion because its principles are drawn from nature and human reasoning.
 In contrast to Deism there are many cultural religions or revealed religions, such as Judaism, Trinitarian Christianity, Islam, Buddhism, and others, which believe in supernatural intervention of God in the world; while Deism denies any supernatural intervention and emphasizes that the world is operated by natural laws of the Supreme Being.
Tonya Cooley (born January 7, 1980, in Visalia, California) is a former cast member on MTV's reality television series, "", the 11th season of "The Real World", which aired in 2002.
 She was then a regular on the spin-off series, "Real World/Road Rules Challenge", participating in eight challenges, with her last being in 2009.
 She also posed for "Playboy" as a Cyber Girl of the Week and appeared in an episode of the Cinemax adult series "The Erotic Traveler".
 The stressful environment of the "Real World/Road Rules Challenge" seasons lead to a bout with alcoholism, but in 2016, BuzzFeed News reported she has gained sobriety in the years since leaving the series and that she is now a salon owner.
 Cooley told the publication, "I am a genuinely happy person now."
Peter Coppola is a hair stylist, salon owner, and businessman.
 He has opened 34 salons throughout his career.
 He is also the owner of Peter Coppola Keratin Concept in Boca Raton, Florida.
Tabatha Takes Over (formerly "Tabatha's Salon Takeover") is an American reality television series on the Bravo network, in which former "Shear Genius" contestant and hair salon owner, Tabatha Coffey helps failing salons turn around in one week.
 The series premiered on August 21, 2008 and is produced by Reveille Productions, a division of Shine Group.
Tabatha Coffey (born 17 May 1967) is an Australian hairstylist, salon owner, and television personality.
 Her participation as a contestant on the television show "Shear Genius" led to her own fame in the US.
 She was given a television show, "Tabatha Takes Over", which airs on the US cable television network Bravo.
 In France it airs on 6ter's free channel and in Australia it airs on Foxtel's pay television network Arena as well as on Network Ten.
Cicada 3301 is a name given to an organization that on six occasions has posted a set of puzzles and alternate reality games to possibly recruit codebreakers/linguists from the public.
 The first internet puzzle started on January 4, 2012, and ran for approximately one month.
 A second round began one year later on January 4, 2013, and a third round following the confirmation of a fresh clue posted on Twitter on January 4, 2014.
 The stated intent was to recruit "intelligent individuals" by presenting a series of puzzles which were to be solved.
 No new puzzles were published on January 4, 2015.
 However, a new clue was posted on Twitter on January 5, 2016.
 In April 2017 another PGP signed message was found: "Beware false paths.
 Always verify PGP signature from 7A35090F."
 That message explicitly denies the validity of any unsigned puzzle, as recently as April 2017.
The System of Nature or, the Laws of the Moral and Physical World ("Système de la Nature ou Des Loix du Monde Physique et du Monde Moral") is a work of philosophy by Paul-Henri Thiry, Baron d'Holbach (1723–1789).
 It was originally published under the name of Jean-Baptiste de Mirabaud, a deceased member of the French Academy of Science.
 D'Holbach wrote and published this book – possibly with the assistance of Diderot but with the support of Jacques-André Naigeon – anonymously in 1770, describing the universe in terms of the principles of philosophical materialism: The mind is identified with brain, there is no "soul" without a living body, the world is governed by strict deterministic laws, free will is an illusion, there are no final causes, and whatever happens takes place because it inexorably must.
 Most notoriously, the work explicitly denies the existence of God, arguing that belief in a higher being is the product of fear, lack of understanding, and anthropomorphism.
Janine Jarman (born April 17, 1981) is an American hairstylist, salon owner, and American television personality.
 Her participation as a contestant on the television show "Shear Genius" led her to style several famous clients including Fergie, Scarlett Johansson and Christina Applegate.
 She served as the go-to stylist for Carmen Electra and the girl group The Pussycat Dolls.
 She owns Hairroin salon in Hollywood, California.
Paul-Henri Thiry, Baron d'Holbach (] ), was a French-German author, philosopher, encyclopedist and prominent figure in the French Enlightenment.
 He was born Paul Heinrich Dietrich in Edesheim, near Landau in the Rhenish Palatinate, but lived and worked mainly in Paris, where he kept a "salon".
 He was well known for his atheism and for his voluminous writings against religion, the most famous of them being "The System of Nature" (1770).
Kafir (Arabic: كافر‎ ‎ "kāfir "; plural كفّار "kuffār "; feminine كافرة "kāfirah ") is an Arabic term (from the root K-F-R "to cover") meaning "unbeliever", or "disbeliever".
 The term alludes to a person who rejects or disbelieves in God and the teachings of the Islamic prophet Muhammad, and denies the dominion and authority of God; or otherwise does not heed the beliefs and prescriptions held by the religion of Islam.
 It is used as a derogatory term.
 Unbelief is called "kufr".
 "Kafir" is sometimes used interchangeably with "mushrik" (مشرك , those who commit polytheism), another type of religious wrongdoer mentioned frequently in the Quran and Islamic works.
 The practice of declaring another self-professed Muslim a kafir is known as "takfir".
 The person who denies the existence of a creator is called "Dahriya".

Question: Which book was written by an atheist salon owner and explicitly denies the existence of God?
Answer: The System of Nature