His boyhood was marked by the longing for mountains, and distant lands, laying the ground for his later interest in geology and astronomy.

His potential artistic and literary talents were recognized early, and encouraged by his art teacher at grammar school.

At the age of fifteen, Pešek acquired a painter's easel, and began to practice his hobby earnestly.

In 1967, Pešek wrote his first science-fiction novel, Log of a Moon Expedition, which he illustrated in black and white.

He also illustrated the excellent Bildatlas des Sonnensystems (1974), with German text by Bruno Stanek.