I am completely puzzled by the negative reviews for this bag.  I think it is extremely effective and have purchased two.  There are three outside pockets - one for credit cards, phone, keys and chapstick.  One large zipper pocket for papers, and the back zip pocket.  So everything I need to get to is readily available.  The inside of the bag is big enough for my bike headlight, tail light, and lock.  It holds a letter size manilla file to bring home from work.  Or my knitting.  Or my book and water bottle.  I think some people are frustrated with the bag if they put little things in the main central opening.  The transition from a shoulder style to a backpack is easy and works especially well if I'm riding the bus.  I think it is just perfect.  I know this will change, but right now I think it is the only bag I'll ever need....  ;-)