who are the thinkers of upanishads ?

Upanishads are the philosophical texts of Hindu religion,  believed to have been created by  several sages over many centuries.They have been attributed to several authors: Yajnavalkya and Uddalaka Aruni feature prominently in the early Upanishads. Other important writers include Shwetaketu, Shandilya, Aitreya, Pippalada and Sanat Kumara.