Mindfulness of breathing
Just watching the breath come in and go out - the simplest practice, and a complete road to awakening.
"Mindfulness of breathing" (ānāpānasati, from āna-apāna, "in-breath and out-breath," and sati, "mindfulness") is meditation that uses the natural breath as its anchor. You simply notice the breath flowing in and flowing out, again and again, returning attention to it gently whenever the mind wanders off. It is one of the oldest and most widely taught practices in Buddhism, present across all the traditions, and the Buddha himself is described as having practiced and praised it.
Its beauty is that it is always available - the breath is with you wherever you are - and that it works on two levels at once. First, resting attention on the breath calms and steadies the mind, drawing it out of restless thinking into a settled, collected state. Second, the very same practice opens into insight: as you watch closely, you begin to notice directly how each breath, each sensation, each mental state rises and passes, never staying the same. That firsthand seeing of constant change is exactly the kind of understanding the path aims to deepen.
The early teaching lays out mindfulness of breathing as a full, sixteen-step progression that begins with simply feeling the long and short breath and gradually widens to embrace feelings, the mind, and insight into impermanence and letting go. So although it can be described in a single sentence - watch the breath - it is taught as a complete path in itself, gentle enough for a beginner's very first sitting yet rich enough to carry a practitioner all the way. This is why it remains, for so many, the natural place to start.
Key passages(20)
Keeping the Breath in Mind & Lessons in Samadhi · Ajahn Lee Dhammadharo
Mindfulness with Breathing: A Manual for Serious Beginners · Buddhadāsa Bhikkhu
The Issue at Hand: Essays on Buddhist Mindfulness Practice · Gil Fronsdal
The Manuals of Dhamma · Ledi Sayadaw
Real Happiness: The Power of Meditation · Sharon Salzberg
The Miracle of Mindfulness: An Introduction to the Practice of Meditation · Thich Nhat Hanh
The Essentials of Buddha-Dhamma in Meditative Practice · Sayagyi U Ba Khin
The Way to Ultimate Calm: Selected Discourses of Webu Sayadaw · Webu Sayadaw