Who is the author of (Ghost Dance): The Adventures of Goopy and Bagha?

A clip from the Goopy Gyne Bagha Byne where the king of ghosts ("bhuter raja") grants Goopy and Bagha three boons. Significantly Satyajit Ray used his own voice for the voice of king of ghosts ("bhuter raja"). In this scene king of ghosts is speaking in rhyme. Satyajit Ray praised S.V.Rau (Rauko) for the ghost dance effect by calling it a technical feat.

The story revolves around Gopinath Gyne (alias Goopy, Tapen Chatterjee), the son of a poor Kayastha grocer Kanu Kyne from a village called Amloki. Goopy wants to become a singer but has a hoarse voice. Persuaded by village elders to sing for the king, he does so and is driven out of Amloki on a donkey for waking the king with his terrible singing. Exiled into a forest, he meets Bagha (Rabi Ghosh), another exile from nearby Hortuki sent to the forest - in Bagha's case, due to playing a drum badly. They start singing and drumming, initially to scare off a roaming tiger, and in the process they attract a group of ghosts who are fascinated by their music. The king of ghosts grants them three boons:

They can get food and clothes whenever needed by clapping their hands,
They are given a pair of magic slippers with which they can travel anywhere,
They gain the ability to hold people in awe (literally, their music renders people motionless) with their music.

They travel to Shundi, where a benevolent king appoints them court musicians. However the king of Halla (the long lost brother of the king of Shundi) is planning to attack Shundi, after being poisoned with magic potion that makes him evil, given to the king of Halla by his self-centered prime minister. Goopy and Bagha travel to Halla in an attempt at preventing the attack, but are captured instead. Since they have now lost their slippers, they can't escape by magic, but manage to do so instead by strategy. They arrive singing and drumming when the soldiers are about to launch their attack, capturing the king of Halla, who is returned to Shundi. The two brothers are reunited and Goopy and Bagha marry the daughters of the two kings.