Nyaya and Vaisesika address epistemological questions, the first from the point of view of the subject or knower and the other from the point of view of the object of knowledge. Samkhya and Yoga are cosmological schools, the first addressing the question of the macrocosm and plurality, and the second, unity, the microcosm, and humankind as witness. Mimamsa and Vedanta are primarily metaphysical systems, the former focusing on praxis or means and the latter on the nature of the end.
The focal point of Jainism’s critique is the recognition that the Truth is always relative to a point of view, even if it seems absolute from a particular perspective. The hegemony of a single tradition as custodian of the Truth is thus broken. Buddhism characterizes reality as suffering, and thus finds it essential to demonstrate the impermanence or momentariness (ksanabhangavada) of this reality, as the condition for the possibility of liberation (nirvana) from it.
The Carvakas are materialists representing the lay point of view. Knowledge of their perspective is mainly derived from representations made by philosophers who opposed them.
Here is a comprehensive selection of books covering all schools of Indian Philosophy.<