Joris-Karl Huysmans in the context of "Odilon Redon"

Spiritual naturalism, or naturalistic spirituality combines a naturalist philosophy with spirituality. Spiritual naturalism may have first been proposed by Joris-Karl Huysmans in 1895 in his book En Route.

Long before the term spiritual naturalism was coined by Huysmans, there is evidence of the value system of spiritual naturalism in Stoicism: "Virtue consists in a will that is in agreement with Nature".

Les Soirées de Médan ("Evenings at Médan") is a collection of six short stories by six different writers associated with Naturalism, first published in 1880. All the stories concern the Franco-Prussian War. The contents of the book are as follows:

• L'Attaque du moulin ("The Attack on the Mill") by Émile Zola
• Boule de Suif ("Ball of Tallow") by Guy de Maupassant
• Sac au dos ("Backpack") by Joris-Karl Huysmans
• La Saignée ("Bloodshed") by Henry Céard
• L'Affaire du Grand 7 ("The Affair of the Great 7") by Léon Hennique
• Après la bataille ("After the Battle") by Paul Alexis

The collection took its title from Zola's house at Médan, near Paris, where writers would meet for literary dinners. The authors were often referred to collectively as the "Médan group". The aim of the collection was to promote the ideals of Naturalism, by treating the events of the Franco-Prussian War in a realistic and often unheroic way, in contrast to officially approved patriotic views of the war.

A Black Mass is a ceremony celebrated by various Satanic groups. It has allegedly existed for centuries in different forms, and the modern form is intentionally a sacrilegious and blasphemous parody of a Catholic Mass.

In the 19th century the Black Mass became popularized in French literature, in books such as Satanism and Witchcraft, by Jules Michelet, and Là-bas, by Joris-Karl Huysmans.

Robert André Edouard Baldick, FRSL, (9 November 1927 – 24 April 1972) was a British scholar of French literature, writer, translator and joint editor of the Penguin Classics series with Betty Radice. He was a Fellow of Pembroke College, Oxford.

He wrote eight books, including biographies of Joris-Karl Huysmans, Frédérick Lemaître, and Henry Murger, and a history of the Siege of Paris. In addition, he edited and translated Pages from the Goncourt Journals and other classics of French literature, including Gustave Flaubert's Sentimental Education, Jules Verne's Journey to the Centre of the Earth, and Jean-Paul Sartre's Nausea, as well as works by Chateaubriand and Henri Barbusse and a number of novels by Georges Simenon. In The New Criterion, Eric Ormsby writes that Baldick's The Life of J.-K. Husymans is "able to hold its own with Painter's Proust or Ellman's Joyce".