Meditation is what many believe as being the main goal of yoga, with asana and pranayama being the very helpful stepping stones leading into it. There are different types of meditation and different levels of awareness that can be experienced, but basically we could say that meditation is a relaxed state of mind which is fully present in the moment and without distraction.
Meditation is more than a concentration technique, but does begin with focussing onto the breath and mentally relaxing the various parts of the body. It can be used for many things, including resting and recharging, reducing anxiety, contemplation, healing and self transformation and even distant healing. In the beginning though just being comfortable with the technique and gaining that wonderful sense of clarity, well-being and relaxation is both a necessary and a great start.
Gradually the mind will become more relaxed through a regular meditation practice, more under control, concentrated and fully present in the moment. Restlessness and desires naturally subside and we awaken to an inner spaciousness and peaceful contentment. The body eventually relaxes to a point that our awareness seems to transcend it and go deeper into the more subtle layers of our being. Here we can experience ourselves as energy and awareness without dimension and this can become quite blissful and produce a profound state of consciousness and affection as we touch and experience our true core and uncluttered self. Although it can be quite profound it can also be totally practical to every day, in that when we are more relaxed and happy everything in life is improved. We feel better about ourselves and can relate better to the people around us, work becomes easier and everything we do and experience becomes more satisfying. If our goal is to be happy then meditation is a well known path that can lead us there. It needs nothing, is simple to understand and easy to practice.
Below is a condensed article written by Swami Bhajanananda who tries to explain meditation and concentration and their difference within Vedantic Yoga philosophy.
Meditation he says is not just an ordinary type of concentration. In ordinary concentration the mind is focused onto an external object or a mental idea, but real meditation is a complete reversal of this process of perception. It means turning the mind or the self back upon its source. In most forms of ordinary concentration the sense organs are active and contact with the external world is not cut off. But during meditation, which needs a higher degree of concentration the mind alone is active and contact with the external world is cut off. According to Patanjali, before we attempt dhyana (meditation) the 7th limb of yoga, we should gain proficiency in dharana (concentration) the 6th limb, or meditation will not be possible. True meditation is not concentration he says, or holding a mind with effort onto an external object or internal idea, but the single pointed and effortless absorption of awareness into the nature of its continuum.
The mind is always moving and creating, but meditation is an attempt to make the mind stop creating by seeking the source of experience. In Vedanta philosophy, experience is also seen as a function of the mind, but its real source (consciousness) is in the Atman or the true Self. Meditation is an attempt to isolate our true Self from the mental clutter and to discover the Uncreated or the Absolute of being. Until we are made aware most of us seek this totality through creative activity in the outer world, constantly trying to fill the void, which meditation seeks to illuminate first through an inward orientation of consciousness and to experience the total bliss and completeness of our essential and spiritual reality. Vedanta holds that every human being is potentially divine and that his or her true self is a part of the Supreme Self. The goal of yoga and the highest form of meditation is the unalloyed experience of this Communion and a Spiritual life is the discovery & awakening of this eternal relationship, a means of uniting the individual self with Supreme Self, the divine and eternal nature of our truth.