Austin Freeman was the youngest of the five children of tailor Richard Freeman and Ann Maria Dunn. He first trained as an apothecary and then studied medicine at Middlesex Hospital, qualifying in 1887. The same year he married Annie Elizabeth with whom he had two sons. He entered the Colonial Service and was sent to Accra on the Gold Coast.

In 1891 he returned to London after suffering from blackwater fever but was unable to find a permanent medical position, and so decided to settle down in Gravesend and earn money from writing fiction, while continuing to practice medicine. His first stories were written in collaboration with Dr John James Pitcairn (1860-1936), medical officer at Holloway Prison and published under the nom de plume "Clifford Ashdown". His first Thorndyke story, The Red Thumb Mark, was published in 1907 and shortly afterwards he pioneered the inverted detective story, in which the identity of the criminal is shown from the beginning: some short stories with this feature were collected in The Singing Bone in 1912. During the First World War he served as a Captain in the Royal Army Medical Corps and afterwards produced a Thorndyke novel almost every year until his death in 1943.

Freeman claimed to have invented the inverted detective story in his 1912 collection of short stories The Singing Bone. "Some years ago I devised, as an experiment, an inverted detective story in two parts. The first part was a minute and detailed description of a crime, setting forth the antecedents, motives, and all attendant circumstances. The reader had seen the crime committed, knew all about the criminal, and was in possession of all the facts. It would have seemed that there was nothing left to tell, but I calculated that the reader would be so occupied with the crime that he would overlook the evidence. And so it turned out. The second part, which described the investigation of the crime, had to most readers the effect of new matter."

"Indicative of his power is the fact that Mr. Polton Explains, in some ways his best novel, was written in part in a bomb shelter in 1939, when Freeman was 77 years old. ... For the first twenty-five years of his career, at least, he dominated the world of British detective fiction. ... Freeman was always in the forefront of the form. Today, with Chesterton, who is remembered for other reasons, he is one of the very few Edwardian detective story writers who are still read."

"Raymond Chandler, whose essay 'The Simple Art of Murder' did much toward demolishing the classical detective story, had this to say in a letter to Hamish Hamilton, the British publisher: 'This man Austin Freeman is a wonderful performer. He has no equal in his genre, and he is also a much better writer than you might think, if you were superficially inclined, because in spite of the immense leisure of his writing, he accomplishes an even suspense which is quite unexpected ... There is even a gaslight charm about his Victorian love affairs, and those wonderful walks across London ...' Most of us agree with Chandler."

• Travels and Life in Ashanti and Jaman (1898)
• Social Decay and Regeneration (1921) (with an introduction by Havelock Ellis)

Thorndyke novels and story collections

• The Red Thumb Mark (1907)
• John Thorndyke's Cases (1909), published in the USA as Dr. Thorndyke's Cases [story collection]
• The Eye of Osiris (1911), published in the USA as The Vanishing Man
• The Mystery of 31 New Inn (1912)
• The Singing Bone (1912), published in the USA as The Adventures of Dr Thorndyke [story collection]
• A Silent Witness (1914)
• Helen Vardon's Confession (1922)
• The Cat's Eye (1923)
• Dr. Thorndyke's Casebook (1923), published in the USA as The Blue Scarab [story collection]
• The Mystery of Angelina Frood (1924)
• The Shadow of the Wolf (1925)
• The Puzzle Lock (1925) [story collection]
• The D'Arblay Mystery (1926)
• A Certain Dr. Thorndyke (1927)
• The Magic Casket (1927) [story collection]
• As A Thief in the Night (1928)
• The Famous Cases of Dr. Thorndyke (1928), published in the USA as The Dr Thorndyke Omnibus [These two volumes differ in the number and arrangement of stories].
• Mr. Pottermack's Oversight (1930)
• Pontifex, Son and Thorndyke (1931)
• When Rogues Fall Out (1932), published in the USA as Dr. Thorndyke's Discovery
• Dr. Thorndyke Intervenes (1933)
• For the Defence: Dr. Thorndyke (1934)
• The Penrose Mystery (1936)
• Felo de Se (1937), published in the USA as Death At The Inn
• The Stoneware Monkey (1938)
• Mr. Polton Explains (1940)
• Dr. Thorndyke's Crime File (1941) -- omnibus including "Meet Dr. Thorndyke" (essay), The Eye of Osiris (novel), "The Art of the Detective Story" (essay), The Mystery of Angelina Frood (novel), "5A King's Bench Walk" (essay), and Mr. Pottermack's Oversight (novel).
• The Jacob Street Mystery (1942), published in the USA as The Unconscious Witness

The short-story collections are:

• John Thorndyke's Cases (1909) (published in the United States as Dr. Thorndyke's Cases).
• The Singing Bone (1912) (published in the United States as The Adventures of Dr. Thorndyke).
• Dr. Thorndyke's Casebook (1923) (published in the United States as The Blue Scarab)
• The Puzzle Lock (1925)
• The Magic Casket (1927)

These five collections contain together 38 from the below mentioned 40 stories. The two other Thorndyke stories were published in The Great Portrait Mystery and other stories (1918). This book contains 7 stories, but only two about Thorndyke. The titles of the 2 Thorndyke stories are The missing mortgagee and Percival Bland's proxy.

Two different omnibus editions of the collected Dr. Thorndyke short stories exist. The British edition is R. Austin Freeman, The Famous Cases of Dr. Thorndyke: Thirty-seven of His Criminal Investigations as set down by R. Austin Freeman (London: Hodder & Stoughton, 1929 and later reprintings). The American edition is R. Austin Freeman, The Dr. Thorndyke Omnibus: 38 of His Criminal Investigations as set down by R. Austin Freeman (New York: Dodd, Mead, 1932 and later reprintings). The American edition includes one story, "The Mandarin's Pearl," printed in the first Thorndyke short-story collection, John Thorndyke's Cases, but omitted from the British omnibus. Two other stories, though also appearing in the first Dr. Thorndyke short-story collection, John Thorndyke's Cases, were omitted from the British and American editions of the omnibus collection: "The Man with the Nailed Shoes" and "A Message from the Deep Sea."

The order in the list appearing below is that of the American edition, which reprinted the five collections of stories in the following order (with two omissions noted below): The Singing Bone [UK 01-04], The Great Portrait Mystery and other stories [UK 05-06], The Singing Bone [UK 07], Dr. Thorndyke's Cases, The Magic Casket, The Puzzle Lock, and The Blue Scarab. The British edition gives the stories in a different order from that of the American edition, indicated below by a bracketed note appearing after each story title giving its place in the British edition, denoted by the abbreviation UK and a two-digit number.

The first six stories of the list are "inverted" detective stories, divided into two parts; in the first part of each story, Freeman presented an account of the commission of crime, and then, in the second part, he presented an account, as told by Thorndyke's colleague Dr. Christopher Jervis, of Dr. Thorndyke's solution of the crime. These inverted stories are generally deemed by critics and scholars of the field to be his most creative contributions to the writing of detective stories, but the remaining stories, called "direct" stories, are also well-wrought and entertaining.

A modern publisher, Battered Silicon Dispatch Box, has issued a 10-volume edition of the complete works of R. Austin Freeman, including all the Thorndyke novels and short stories. Its current availability is unclear.

• The Case of Oscar Brodski [UK 01]
• A Case of Premeditation [UK 02]
• The Echo of a Mutiny [UK 03]
• A Wastrel's Romance [UK 04]
• The Missing Mortgagee [UK 05]
• Percival Bland's Proxy [UK 06]
• The Old Lag [UK 07]
• The Stranger's Latchkey [UK 08]
• The Anthropologist at Large [UK 09]
• The Blue Sequin [UK 10]
• The Moabite Cipher [UK 11]
• The Mandarin's Pearl [omitted from British edition]
• The Aluminium Dagger [UK 12]
• The Magic Casket [UK 13]
• The Case of the White Footprints [UK 31]
• The Blue Scarab [UK 32]
• The New Jersey Sphinx [UK 33]
• The Touchstone [UK 34]
• A Fisher of Men [UK 35]
• The Stolen Ingots [UK 36]
• The Funeral Pyre [UK 37]
• The Puzzle Lock [UK 22]
• The Green Check Jacket [UK 23]
• The Seal of Nebuchadnezzar [UK 24]
• Phyllis Annesley's Peril [UK 25]
• A Sower of Pestilence [UK 26]
• Rex v. Burnaby [UK 27]
• A Mystery of the Sand-hills [UK 28]
• The Apparition of Burling Court [UK 29]
• The Mysterious Visitor [UK 30]
• The Contents of a Mare's Nest [UK 14]
• The Stalking Horse [UK 15]
• The Naturalist at Law [UK 16]
• Mr. Ponting's Alibi [UK 17]
• Pandora's Box [UK 18]
• The Trail of Behemoth [UK 19]
• The Pathologist to the Rescue [UK 20]
• Gleanings from the Wreckage [UK 21]
• The Man with the Nailed Shoes [omitted from both omnibus editions]
• A Message from the Deep Sea [omitted from both omnibus editions]

There also exist two another Thorndyke stories, which were uncollected during his lifetime. 31, New Inn (circa 1905) is a short story, later completely rewritten as a full-length novel, The Mystery of 31 New Inn. Other people suggest 1911 as year of publication. The other short story is The Dead Hand (1912) that was later developed into the novel The Shadow of the Wolf.31, New Inn was published in The best Dr. Thorndyke detective stories (1973), edited by E.F. Bleiler, and in volume I of the Freeman omnibus, published by Battered Silicon Dispatch Box. The Dead Hand is published in volume IX The Uncollected Freeman, by Battered Silicon Dispatch Box. The Dead Hand is also published in Detection by gaslight, 14 Victorian detective stories, an anthology by Douglas Greene (1997).

Other novels and collections

• The Adventures of Romney Pringle, with John Pitcairn, as Clifford Ashdown (1902)
• The Further Adventures of Romney Pringle, with John Pitcairn, as Clifford Ashdown (1903 in Cassell's Magazine; first book publication, 1970)
• From a Surgeon's Diary, with John Pitcairn, as Clifford Ashdown (1904-5 in Cassell's Magazine; first book publication, 1977)
• The Golden Pool: A Story of a Forgotten Mine (1905)
• The Unwilling Adventurer (1913)
• The Uttermost Farthing (1914 in the USA, only; first British publication, 1920, as "A Savant's Vendetta")
• The Exploits of Danby Croker (1916)
• The Great Portrait Mystery (1918)
• The Surprising Experiences of Mr Shuttlebury Cobb (1927)
• Flighty Phyllis (1928)
• The Queen's Treasure, with John Pitcairn, as Clifford Ashdown (written around 1905/6, but not published until 1975)