What is the 'Unmanifest' or causal body, and what is the only way to achieve liberation from it?

The 'Unmanifest' (Avyakruta) is described as the causal (karana) body of the soul, which is characterized by the reflection of consciousness and is the cause of pure ignorance (Avidya). This ignorance of the Soul is the cause of its existence. According to Chapter 50, the only way to remove this causal body is through the attainment of knowledge of the unity between Brahman and the Soul. This realization allows one to abide in one's own true form, a state which is itself defined as liberation, or Moksha. The text emphasizes that there is no other form of liberation apart from this.