Simpkin, Marshall, Hamilton, Kent and Co. Ltd.
From The Arthur Conan Doyle Encyclopedia

Simpkin, Marshall, Hamilton, Kent and Co. Ltd. was a British publishing company based in London. The company was founded as Crosby and Co. by Benjamin Crosby. William Simpkin and Richard Marshall were Crosby's assistants. Upon Crosby's illness in 1814, the company name changed to Simpkin and Marshall. In 1890-1891 the firm expanded and became Simpkin, Marshall, Hamilton, Kent and Company.
The company was trade agent for J. W. Arrowsmith and The Psychic Press which both published Arthur Conan Doyle's novels and essays between 1892 and 1929.
Conan Doyle published by Simpkin, Marshall, Hamilton, Kent and Co.
1892
- 31.10.1892 : The Great Shadow (Arrowsmith's Christmas Annual) 1/-
- ---.11.1892 : The Great Shadow 1/6 1/-
- ---.11.1892 : The Great Shadow (Arrowsmith's Bristol Library vol. II)
1892-1893
- ---.12.1892 : The Great Shadow (issued 1893)
1893
- ---.08.1893 : The Great Shadow and Beyond the City (9 ill. by James Greig and 9 by Paul Hardy) 3/6
1893-1914
- The Great Shadow and Beyond the City (several re-imp. as Arrowsmith's 3/6 Series)

1927
- 21.03.1927 : Pheneas Speaks 2/6 3/6
1928
- ---.07.1928 : Psychical Experiences of a Musician, by Florizel Von Reuter (introduction by Sir Arthur Conan Doyle)
1929
- ---.11.1929 : The Spiritual Adventures of a Business, by T. A. R. Purchas (foreword by Sir Arthur Conan Doyle)