Mundakopanishad commentary

*कस्मिन्नु भगवो विज्ञाते सर्वमिदं विज्ञातं भवतीति ॥ ३ ॥*

What is that knowledge by knowing which all other knowledge is known?

http://www.swami-krishnananda.org/mundak1/mundak1_1.html