Concept:
The *Abhidharmakośa* (Treasury of Abhidharma) is arguably the most important encyclopedic work on early Buddhist philosophy. It summarizes the complex Abhidharma teachings of the Sarvāstivāda school. The work consists of the *Kārikās* (verses) and a *Bhashya* (commentary).
Step 1: Identifying Vasubandhu's contribution.
The Abhidharmakośakārikā was authored by the great master Vasubandhu (4th-5th Century CE). Interestingly, Vasubandhu wrote the verses to synthesize the Vaibhāṣika teachings, but in his own commentary (Bhashya) on these verses, he often criticized them from a Sautrāntika perspective. This work remains a core textbook for Buddhist monks across all traditions.
Step 2: Background on other scholars.
• Nāgasena: Known for the *Milinda Panha* (Questions of King Milinda).
• Śrīlāta and Kumāralāta: Significant Sautrāntika teachers, but they did not author the *Kośa*.