Four : The Levels of Shamatha and Vipassana
This point will only be touched upon here, as it is explained completely in the detailed explanations which follow. There are nine levels of shamatha and four levels of vipashyana, which describe the stages of meditation.
The nine levels of shamatha are:
In Tibetan there are two different words for examination and analysis, where examination means a coarse examination and analysis implies a more profound and detailed analysis. So there is a difference between these two words in Tibetan which does not come across in English, that one is more subtle than the other. When shamatha has become natural, you can accomplish the four levels of vipashyana.