Portable writing desks were created for people whose jobs require constant travel so they have a surface to write on wherever they go. A portable writing desk is typically a lidded box that serves as a writing surface, with space inside to hold supplies. The best designs have a sloped top to improve penmanship. There are various styles available, including some that roll on wheels or are meant to use on one's lap. Portable writing desks provide a useful tool for those who must work while traveling or in different locations.