This document compares major e-reader devices, including the Amazon Kindle, Barnes & Noble Nook, Sony Reader, and Apple iPad. It outlines their prices, sizes, connectivity features, storage capacities, battery lives, supported file formats, and included accessories. Key differences include screen sizes from 6 to 10 inches, storage from 2GB to 64GB, battery life from 2 days to a month, and price ranges from $139 to $699 depending on model and connectivity. The Kindle and Nook offer the largest selection of ebooks around 2.5 million, while Apple does not provide specific numbers.