This series of 12 books is a collection of dialogues with M. as written down by Swami Nityatmananda, in the style of The Gospel of Sri Ramakrishna.

You'll find information about Ramakrishna and his disciples that is unavailable anywhere else. It's an impressive collection of stories that will be of special interest to the Ramakrishna enthusiast. Unfortunately, the English is in places difficult to read because the translation is strongly "Indian-English." Furthermore, some of the books are printed on poor quality paper, slightly yellowed. But again, you'll find stories not available elsewhere.