Backpacks are quickly becoming the bag of choice for travel. With a wide variety of sizes and specializations, backpacks can transport clothes, accessories, computers and documents in a single bag that is securely attached to the person. Backpacks can be used as carry-ons or sometimes as a "personal" bag in addition to carry-on luggage. Backpacks are also useful because they can be packed and left alone, not needing to be carried, meaning your hands are free, and are secure since they can't be removed and stolen like shoulder bags or totes.