Bhakti Ratnakara (The Jewel-filled Ocean of Devotional Service

Bhakti-ratnakara is a devotional text written by Narahari Cakravarti that highlights the lives and teachings of prominent saints, particularly the Six Goswamis of Vrindavan, and the importance of bhakti (devotion) to Lord Krishna. The text outlines the principles of devotional service, recounts the stories of great devotees, and emphasizes the power of chanting the Holy Name and the importance of humility, surrender, and service in cultivating a deep spiritual connection with Krishna. 
This work is an essential part of the Gaudiya Vaishnavism tradition and serves as both a historical account and a guide to devotional practice.