Thumb + Pen Interaction on Tablets addresses the simultaneous, and complementary, use of pen & touch modalities for interaction in laptop scenarios, such as when using a Surface tablet on the couch, where the nonpreferred hand must often hold the device itself. In this case, the thumb is available and sufficiently mobile to manipulate many controls, enabling a whole new space of “thumb + pen” interactions. This can allow one to readily interleave use of a pen between annotation and cell-selection on a spreadsheet, for example, or to select cells and copy them to another (possibly distant) location on the sheet—thus illustrating how pen and touch (via the thumb) can afford a far more casual form of productivity, even when one is just kicking back on the couch with such devices.