I have a satchel that I've used for years to carry things back and forth to work, including my lunch. Recently things changed and I needed to start carrying a laptop too. The satchel was designed to hold a 15" laptop, but it doesn't have much padding, and once you add a laptop, there wasn't much extra space for anything else, like my lunch. I also ride a motorcycle to/from work when weather permits, so I needed something large enough to carry all my normal stuff, plus a laptop, and still be small enough to fix on the rear seat of my motorcycle; held down with a couple of bungee straps. I searched Amazon, and several local retail stores, and I did find a different one that I though might work, but I still wasn't sure. I'm glad I held off because when I saw this one, I knew it would fit my needs perfectly. One thing not mentioned or pictured online is an removable inner padded laptop sleeve with a padded flap that completely encases your laptop. My 15" laptop fits perfectly. The laptop compartment of the backpack is also moderately padded, so if your laptop is too big for the sleeve, you don't need to use it and your laptop will still have some protection. This backpack has 3 main zippered compartments. What's impressive about this particular make/model is the middle compartment. It's almost as big as the laptop compartment. I has a nylon divider, but it's not a 50/50 split. More like 70/30. It's big enough to fit a 2nd (smaller) laptop, several college text books, or my lunch in the bigger section, and several folders in the smaller one. The 3rd main compartment is the front one. You could probably fit a 10.1" tablet (with bumper or case) in this compartment if you wanted to. It has a place for pens or pencils, and several pockets for smaller items like a calculator, business cards, etc. The are also 4 small zippered compartments. One on each side, one in the front, and one at the top between the laptop and middle compartments. This top one also includes a pass-though for headphones. Overall this backpack measures about 18" tall, 13 - 14" wide, and about 7" deep.