Osho, also known as Bhagwan Shree Rajneesh, was a self-realized spiritual teacher. He taught many people in India and after opening his ashram in Pune, India in 1974 he attracted large numbers of Westerners. His sex-positive attitude earned him the title of "sex guru" in international press. His teachings emphasized the importance of meditation, awareness, love, celebration, creativity and humor. His teachings strongly influence the Neo-Tantra  and New Age movements.
Here  is Osho’s response to the question: What is Meditation?

"Meditation is a simple process
Of watching your own mind.
Not fighting with the mind
Not trying to control it either
Just remaining there, a choiceless witness.
Whatsoever passes you simply take note of it
With no prejudice for or against.
You don't call it names
That this should not come to my mind
That this is an ugly thought and
This is a very beautiful and virtuous thought.
You should not judge
You should remain non-judgmental
Because the moment you judge, you lose meditation.
You become identified.
Either you become a friend or you become a foe.
You create relationships.
Meditation means
Remaining unrelated with your thought process
Utterly unrelated, cool, calm
Watching whatsoever is passing.
And then a miracle happens:
Slowly slowly one becomes aware
That less and less thoughts are passing.
The more alert you are, the less thoughts pass
The less alert you are, the more thoughts pass.
It is as if traffic depends on your awareness.
When you are perfectly aware
Even for a single moment, all thinking stops.
Immediately, there is a sudden stop
And the road is empty, there is no traffic.
That moment is meditation.

Slowly slowly those moments come more and more
Those empty spaces come again and again
And stay longer.
And you become capable of moving easily
Into those empty spaces with no effort.
So whenever you want you can move
Into those empty spaces with no effort.
They are refreshing, rejuvenating
And they make you aware of who you are.
Freed from the mind you are freed
From all ideas about yourself.
Now you can see who you are without any prejudice.
And to know oneself
Is to know all that is worth knowing.
And to miss self-knowledge is to miss all.
A man may know everything in the world
But if he does not know himself
He is utterly ignorant
He is just a walking Encyclopaedia Britannica.

Freedom without awareness is only an empty idea.
It contains nothing.
One cannot be really free without being aware
Because your unconscious goes on dominating you
Your unconscious goes on pulling your strings.
You may think, you may believe that you are free
But you are not free, you are just a victim
Of natural forces, blind forces.

So there are two types of people. The majority
Follows the tradition, the society, the state.
The orthodox people, the conventional
The conformists ― they follow the crowd
They are not free.
And then there are a few rebellious spirits
Drop-outs, bohemians, artists
Painters, musicians, poets;
They think they are living in freedom
But they only think. Just by rebellion
Against the tradition you don't become free.
You are still under the rule of natural instincts.
You are possessed by lust, by greed, by ambitions.
And you are not a master of these things
You are a slave. Hence I say
Freedom is only possible through awareness.
Unless one transforms ones unconsciousness
Into consciousness there is no freedom.

And that is where only very few people
Have succeeded ― a Jesus, a Lao Tzu
A Zarathustra, a Buddha
Just a few people
Who can be counted on one's fingers.
They have really lived in freedom
Because they lived out of awareness.

That has to be the work for every seeker:
To create more and more awareness.
Then freedom comes of its own accord.
Freedom is the fragrance of the flower of awareness."

Except from Osho: Eighty Four Thousand Poems, Chapter 5