The Four Foundations of Mindfulness are:

1. Mindfulness of the Body (Kāyānupassanā): This involves being aware of the body, including breathing, postures, physical sensations, and the body's impermanence[1][2][4].

2. Mindfulness of Feelings (Vedanānupassanā): This focuses on observing pleasant, unpleasant, and neutral feelings as they arise and pass away, without getting attached to them[1][2][4].

3. Mindfulness of Mind/Consciousness (Cittānupassanā): This involves observing the general state of the mind, including thoughts, emotions, and mental states[1][2][4].

4. Mindfulness of Dhammas/Mental Objects (Dhammānupassanā): This encompasses awareness of various mental phenomena and Buddhist teachings, including the Five Hindrances, the Five Aggregates, the Six Sense Bases, the Seven Factors of Enlightenment, and the Four Noble Truths[1][2][3].

These foundations form a progressive sequence, moving from gross to subtle aspects of experience. They are designed to develop both concentration and insight, revealing the impermanent, unsatisfactory, and selfless nature of experience[1][4]. The Buddha taught these as a "direct path" for purification, overcoming suffering, and realizing Nibbana (Nirvana)[3].

Practitioners are instructed to observe these aspects of experience with ardency, clear comprehension, and mindfulness, while letting go of attachments to worldly concerns[1]. This practice is considered fundamental in Buddhist meditation and is applicable at all stages of the spiritual path[1].

Citations:

[1] https://www.lionsroar.com/four-foundations-mindfulness-plain-english/

[2] https://www.spiritrock.org/practice-guides/the-four-foundations-of-mindfulness

[3] https://www.lionsroar.com/the-buddhas-four-foundations-of-mindfulness/

[4] https://mindworks.org/blog/four-foundations-of-mindfulness/

[5] https://www.imsb.org/prev/buddhalists/FourFoundationsOfMindfulness.pdf