Rajneesh Chandra Mohan Jain (December 11, 1931 – January 19, 1990), better known during the 1960s as Acharya Rajneesh, then during the 1970s and 1980s as Bhagwan Shree Rajneesh and later taking the name Osho, was an Indian spiritual teacher. He lived in India and in other countries including, for a period, the United States, and inspired the Osho movement, a controversial spiritual and philosophical movement that still has many followers.

Osho taught that the greatest values in life are (in no specific order) awareness, love, meditation, celebration, creativity and laughter. He said that enlightenment is everyone's natural state, but that one is distracted from realising it – particularly by the human activity of thought, as well as by emotional ties to societal expectations, and consequent fears and inhibitions.

He was a prolific speaker (in both Hindi and English) on various spiritual traditions including those of Buddha, Laozi, Krishna, Guru Nanak, Jesus, Socrates, Zen masters, Gurdjieff, Sufism, Hassidism, Tantra and many others. He attempted to ensure that no "system of thought" would define him, since he believed that no philosophy can fully express the truth.

An experienced orator, he said that words could not convey his message, but that his basic reason for speaking was to give people a taste of meditation:

“I am making you aware of silences without any effort on your part. My speaking is being used for the first time as a strategy to create silence in you.
This is not a teaching, a doctrine, a creed. That’s why I can say anything. I am the most free person who has ever existed as far as saying anything is concerned. I can contradict myself in the same evening a hundred times. Because it is not a speech, it has not to be consistent. It is a totally different thing, and it will take time for the world to recognise that a tremendously different experiment was going on.
Just a moment … when I became silent, you become silent. What remains is just a pure awaiting. You are not making any effort; neither am I making any effort. I enjoy talking; it is not an effort.
I love to see you silent. I love to see you laugh, I love to see you dance. But in all these activities, the fundamental remains meditation.”

He was often called the "sex guru" after some speeches in the late 1960s on sexuality. These were later compiled under the title From Sex to Superconsciousness. According to him, "For Tantra everything is holy, nothing is unholy", and all repressive sexual morality was self-defeating, since one could not transcend sex without experiencing it thoroughly and consciously.

Osho said he loved to disturb people – only by disturbing them could he make them think.

Links:
Wikipedia article on Osho
Osho International Foundation