Who is author of novel Titash Ekti Nadir Naam?

Who is author of novel Titash Ekti Nadir Naam? Describe the theme of this novel.

Titash Ekti Nadir Naam is one of the most amazing literary pieces in Bengali literature because
(i) This novel is an epic, the author delicately observed the lifestyle of a marginal community, i.e. the Mallas who live off fishing in the river Titash.
(ii) This novel is about three generations of the Mallas, about their community life, happiness, tragedy portrayed in great details.
(iii) This novel describes the religious traditions, festivals, bhatiali or boat songs and the threat to the Malla community.The life of the community closely tied up with the river. As the river dries up, the community dies too.
(iv) Novelists before Advaita had featured low castes as their protagonists. Titash is special, because the author is, himself belongs to this low caste Malla, community.