NASA's Curiosity Mars rover snapped this image using the camera at the tip of its robotic arm. Even more impressive than the revelation that Martians were bibliophiles is that this book is just 2.5 centimeters across, indicating that the extraterrestrials have excellent vision or are, themselves, quite tiny.
From NASA:
Rocks with unusual shapes are common on Mars, and often were formed by water seeping through cracks in a rock in the ancient past, bringing harder minerals along with them. After eons of being sand-blasted by the wind, softer rock is carved away and the harder materials are all that's left.
