Stated most simply, Meditation is the practice of deep concentration of the mind. The practice involves either altered state of mind or relaxed state of body. Meditation has been around for thousands of years. Evidence of the practice can be found throughout history in many different religions and many different places in the world.
In the past decades, the practice has gained new popularity in the world for its physical, psychological and spiritual benefits. Many people have tried and felt the benefit, then they embrace the practice on daily basis.
In short, meditation is an ancient practice of altering consciousness that can contribute to physical and mental wellbeing.
Because of distorted teachings and different beliefs, there are many, many kinds of different meditation techniques, styles, practices and methods designed for different purposes and taught by different sects and groups. It is very hard to differentiate all the techniques, styles, practices and methods because of the vast amount of information that available in this subject. Nevertheless, here are some popular kinds of meditation
The first meditation I would like to mention is called Mindfulness, also called 'Vipassana', comes from the Buddhist tradition because it was "invented" and taught by the Buddha Gautama himself. In my opinion, mindfulness is the most common form of meditation practiced in this modern world and the most popular meditation taught in commercial meditation schools because of its simplicity.
As the name says, it teaches us to be mindful and alert of everything we do in our lives. It gives us deliberate thought and concentration to everything we do. It's all about 'being present', letting our mind run, and accepting whatever thoughts come up, while practicing detachment from each thought. Mindfulness is taught along with awareness on the breath, though the breathing is often considered to be just one sensation among many others, not a particular focus. This will motivate a better awareness of the diverse situations and surroundings we are in, resulting in a more balanced and relaxed body and nervous system. This type of meditation trains your mind and body to meditate on the things in life that you cannot change, with a great deal of contemplation and rumination on the whole idea. It can be applied to every aspect of life, from eating to exercising, to just breathing and living.
When practicing this kind of meditation, there is no attempt to change the breathing pattern, which limits this practice and makes it observational rather than active. Changing our breathing changes the energy; just watching what our breathing is doing (particularly if your breathing is shallow, as it generally is) means we are stuck in a low-energy state.
The second kind of meditation I would like to mention is Zazen. Zazen is the root of the modern Zen tradition. Zazen comes from Japanese Buddhist tradition and is very hard to practice for those who are not familiar with...