This is the Bear by Sarah Hayes (author) and Helen Craig (illustrator)

The boy, the bear and the dog are the best of friends. But one day the bear gets lost, and his friends must search high and low… Combining a rhyming text with gentle, witty illustrations that include speech bubbles, this lovely book is ideal for sharing at storytime. The speech bubbles create a dual level text that children can read alone or chime in with while being read to, helping them gradually build their reading skills as the hunt for the bear gathers pace!