A series of questions asked by Mahā-Koṭṭhika on psychological topics — e.g., understanding, consciousness, feeling, perception, pure mental consciousness (manoviññāṇa), isolated from the five faculties of bodily sense — the eye of understanding, right outlook, types of rebirth, first jhāna, etc. — and Sāriputta’s answers thereto (M.i.292‑8).
The sutta was probably originally compiled rather as a “lesson” for learners than as a genuine enquiry by Koṭṭhika. It is this sutta that obtained for Koṭṭhika the rank of pre-eminence among those possessing analytical knowledge (paṭisambhidā). AA.i.159.