Alfred Percy Sinnett was a British journalist and occultist who played an important part in the affairs of the Theosophical Society during its first generation. In the early 1880s A.P. Sinnett corresponded with the Mahatmas Koot Hoomi and Morya. In these letters the Masters gave Sinnett the basic ideas of Theosophy on the constitution of man, the planetary chain, the world periods, life after death in Devachan and Kâma-loka, the progress of humanity, Buddha and Nirvana. In 1883 Mr. Sinnett wrote "Esoteric Buddhism" based on his understanding of these teachings. This classic was the first simple exposition of Theosophy in modern times.