Letter written on 15 Oct 1970 (Kusum)
Osho wrote many letters to Ma Kusum Bharti and her husband Kapil, then of Ludhiana. Most were addressed to Kusum, but always asking after Kapil too. All but a few were published in Prem Ke Swar (प्रेम के स्वर). The wiki has images of all but one of those published in PKS, plus a few more.
This letter is dated 15th October 1970. It is one of the few not published in PKS. The letterhead gives Osho's address as CCI Chembers [sic] in Bombay, with his name rendered as Acharya Rajaneesh. The logo is a one-colour version of the Jeevan Jagriti Kendra logo (dark green), but a different colour than the name and address (dark blue). Not many letters were written using this letterhead, as he did not stay long in CCI Chambers.
See also Letters to Kusum and Kapil