Mobile phones have become ubiquitous in today’s society. However, mobile users are no longer satisfied with simple phones but instead expect ever more powerful functions to be available from their mobile devices. Advanced phones known as smartphones allow mobile users to perform a wide variety of advanced handheld functions such as browsing the mobile Internet or finding a nearby theater showing a specific movie. The design and development of these new, improved handheld functions require the help of handheld computing research. This article introduces handheld computing research using three themes: (i) mobile handheld devices, (ii) mobile computing, and (iii) current issues in handheld computing research. Information about other handheld topics of interest to researchers is given in the last section.