Sadhu Vani

That form of Vishnu shown on the Ishopanishad book cover is Keshava. Keshava is one of the twenty-four forms of Vishnu, each distinguished by a particular arrangement of the four symbols — the conch, disc, mace, and lotus — in His four hands.

Keshava, Narayana, Madhava, Govinda, and the other forms are identified according to the specific order in which these symbols are held. The arrangement shown on that cover is specifically the form of Keshava.