Sachchidananda Hirananda Vatsyayan 'Agyeya' (सच्चिदानन्द हीरानन्द वात्स्यायन 'अज्ञेय') (7 March 1911 – 4 April 1987), popularly known by his pen-name Ajneya ("Beyond comprehension"), was a pioneer of modern trends not only in the realm of Hindi poetry, but also fiction, criticism and journalism.