When you're hopping from Tube to Tube, you want a book in bite-size chunks that you can pick up and put down at a moment's notice. Some are quick and light, others are perfect escapism when when you're delayed for half an hour on the Circle Line, and others will make the best use of our time by improving our minds. These are our favourite books for reading when we're on the Underground - but you could read them on any bus, train, plane, donkey or bicycle if you wanted. ...Maybe not the last one. Why not [mailto:sue@thebookbag.co.uk tell us] about your favourites?