What's That Colour is a fun rhyming Questioneers concept board book starring Aaron Slater, Illustrator all about colors from the #1 New York Times bestselling creators of Ada Twist, Scientist and Rosie Revere, Engineer Aaron has yellow. Rosie has red. Mix them together, it's something new instead! Aaron Slater, Illustrator and his fellow Questioners star in their first ever board book all about the dazzling world of colours. What happens when you mix yellow and blue? What about blue and red? What if you mix all the colours together? Andrea Beaty and David Roberts--the #1 New York Times bestselling creators of the Questioneers series--are back with a delightfully rhyming and vibrantly illustrated board book, the first in a brand-new concepts series for preschoolers. Readers will join their favorite Questioneers as they explore numbers, shapes, and feelings in future board books.