Nastaliq is a style of Islamic calligraphy formalized in the 14th century by master calligrapher Mir ‘Ali Tabrizi. Though its exact origins are unclear. The name indicates the combination of elements of two predating styles. Naskh and Ta’liq.

What is meant by Nastaleeq?

An Arabic script developed about the 15th century. Characterized by a tendency to slope downward from right to left, and used mainly for Persian poetical writings and in Urdu and Malay manuscript.

Which Urdu font is used in books?

For Urdu composing Jameel Noori Nastaleeq font is used.

According to wiki pedia

Jameel Noori Nastaleeq is one of the main calligraphic hands used to write the Perso-Arabic script in the Persian and Urdu languages. Traditionally the predominant style in Persian calligraphy.

It was developed in the land of Persia (modern-day Iran) in the 14th and 15th centuries. It is sometimes used to write Arabic language text (where it is mainly used for titles and headings). Its use has always been more popular in the Persian, Urdu and Turkic sphere of influence.

Nastaleeq remains very widely used in Iran, Afghanistan and Pakistan and other countries for written poetry and as a form of art.