Grease and line two 9x13 metal baking pans, leaving a 2-inch overhang.
In a medium saucepan combine sugar, corn syrup, salt, and room temperature water over high heat. Bring to a boil and stir constantly.
Place a candy thermometer in the pan and continue cooking until the sugar mixture reaches 238ºF.
Pour cold water into a medium bowl and sprinkle the gelatin over the water. Let soften for 5 minutes.
Once the sugar mixture reaches 238ºF, pour it into the gelatin mixture and beat it with an electric mixer on low speed. Gradually increase the speed to high, beating until the mixture is very stiff, about 12 minutes.
Add in the vanilla extract and mix until well combined.
Pour the mixture into the two lined pans and smooth the tops with a spatula. Let the marshmallows sit uncovered until completely firm, about 3 hours.
Sift a layer of powdered sugar on top of the marshmallows and onto a work surface.
Remove the marshmallows from the pans and flip over onto the prepared work surface, then remove the parchment paper. Sift a layer of powdered sugar on the top of the marshmallows so all sides are covered.
Use a square cookie cutter or a sharp knife to cut out 24 marshmallow squares. Dip the cookie cutter or knife into powdered sugar between each use to keep the marshmallows from sticking.
Break 24 graham crackers in half into squares – these will be the front and back covers of your books. Break 6 graham cracker sheets into quarters – these will be the spines of your books.
Time to decorate!
In the microwave or a double broiler, melt the milk chocolate and scoop it into a decorating bag fitted with a #2 tip. Using the melted chocolate as an adhesive, attach the graham crackers to the marshmallows to create your books.
Using the milk chocolate, pipe lines around the edges of the cover to form a rectangle (PICTURE at 8:05). Draw a smaller rectangle in the top-center of the cover – this will be the border for the title. Flood the small rectangle.
Once the milk chocolate is completely dry, melt the white chocolate and scoop it into a decorating bag fitted with a #1 tip. Pipe on the book titles with the white chocolate.
TaDa! Your textbook s’mores are ready for you and your classmates to enjoy!