The source mentions a dialogue between Krishna and Uddhava. What book is this from and why was it considered so significant?

The dialogue between Krishna and Uddhava is from the Uddhava Gita, which is presented as a part of the larger Bhagavat text. Chapter 18 describes this as a "very divinely inspired book" and holds it in extremely high regard. Its significance is emphasized by a direct comparison, stating that the dialogue between Krishna and Uddhava is even better than the famous one between Krishna and Arjuna in the Bharata. It is called the "loving speech of Nath," and the text claims that those who perform the reading with faith can attain God instantly. Sai Baba's high esteem for it is shown by his instruction to have it read daily in Shirdi for the salvation of souls.