Hi, Joshvee
0.4-P1 the last update of the game (including all previous updates of the game) driven by story of the game.
While STORYBOOK are something like DLC content for original game (0.4-P1) with additional separate story's that not included in the game.
So i think the better will be buy the game (0.4-P1) and then you can buy a Storybook (if you like the game and you want more).