Alfred Percy Sinnett (18 January 1840 – 26 June 1921) was an English author and theosophist.

His wife Patience is 27, and her mother Clarissa Edenson a "Landowner", is living with them.By 1879, Sinnett had moved to India where he was "... the Editor of The Pioneer, the leading English Daily of India..."[3] He relates in his book, The Occult World that: "...on the first occasion of my making Madame Blavatsky's acquaintance she became a guest at my home at Allahabad and remained there for six weeks..."[4] In 1880 Helena Blavatsky and Henry Steel Olcott visited the Sinnetts at their summer home in Simla.

The Mahatma Letters, which generated the controversy that later helped lead to the split of the Theosophical Society were mostly written to Sinnett or his wife Patience.

[5] Sinnett asked Charles Webster Leadbeater to come back to England to tutor his son Percy and George Arundale.

Using "astral clairvoyance" Leadbeater assisted William Scott-Elliot to write his book The Story of Atlantis, for which Sinnett wrote the preface.