The Hunting of the Snark
This book is available for download with iBooks on your Mac or iOS device, and with iTunes on your computer. Books can be read with iBooks on your Mac or iOS device.
The story follows a crew of ten trying to hunt the Snark, an animal which may turn out to be a highly dangerous Boojum. The only one of the crew to find the Snark quickly vanishes, leading the narrator to explain that it was a Boojum after all.