Dhāraṇā

Translates into “choosing a focus and directing our attention there.” The object of focus can be internal, external or abstract. Examples include: internal – cakraexternal – the flame of a candle or abstract – an idea.

"By Dhahran you preserved long life, while other Yogis perished." The long-live one answered: "No they did not perish, but they got tired of the burden of the human body and gave it up at will."

This diagram is from Shankara philosophy. It displays the layers of what we commonly call the mind. The arrows indicate how we move in and out through the layers in order to create concentration and ultimately Samādhi.

Buddhi (grey layer) comprises of our will, judgement, discernment and the faculty of discrimination.

Ahaṅkāra (golden layer) is the barrier between the transcendent Self and the littler self, that which makes us feel isolated & fragmented.

Manaha is also referred to as Ātman, the root of which is ātma “breath.” This area is generally referred to as the inner Self. It is the place of connection between the physical manifest individual and divineness.

Meditation: Meaning, Properties and Functions of Mind                 Conditions and control of mind are described with links to various how the mind interacts with various systems of our being.

Yoga Sūtras 3.1-3.3  In depth description of the last three rungs of Yoga.

Seeking Samadhi  Judith Lasater explains how concentrative practices evolve.