Krishna book Original Edition - 2 Volumes

The term "Īśopaniṣad" derives from "Īśa," meaning the supreme controller or Lord, and "Upaniṣad," referring to the knowledge that brings one closer to the Supreme Personality of Godhead, Kṛṣṇa

Sri Isopanisad states that everything belongs to the Supreme Personality of Godhead Lord Krsna.
Everything exists on the energy of the Supreme Lord. This is also confirmed in Bhagavad-gita. Because everything is produced of His energy and exists on His energy, the energy is not different from Him--but still the Lord declares, I am not there.

In the Vedic age a disciple heard from the Spiritual Master messages which were coming down in disciplic succession, so a disciple, whatever he heard from his bona fide Spiritual Master, would recite. The Vedic mantras are known as Sruti, to hear from authoritative source and then repeat it, chanting. So there is no question of who wrote it, it is said that no human being has compiled them. Later on, before the beginning of Kali Yuga, all Vedic mantras were written in books, most of them were done by Srila Vyasadeva Mahamuni and his different disciples.

This Īśopaniṣad is part of the Yajur Veda, one of the four Vedas, and consequently, it contains information concerning the proprietorship of all things existing within the universe.

The Śrī Īśopaniṣad consists of eighteen mantras, plus an invocation mantra, which together reveal the essence of the Absolute Truth.