The Rosary has a long and rich tradition in the Church. The Blessed Virgin Mary requested its daily recitation in her apparitions at Fatima in 1917. Numerous popes, saints, and religious have written about it. The Secret of the Rosary by St Louis de Montfort (b. 1673- d. 1716) is worth a read if you would like to learn more about the Rosary.
The Secret of the Rosary may be read online at: rosary-center.org