In this chapter, we survey recent research on multibrain applications. That is, applications in which synchronized brain activity of multiple users is measured and integrated to use their joint brain activity to make real-time decisions about communication with and control of devices in smart environments. Interestingly, we can go back to early brain–computer interface research of the 1970s to see many ideas and sometimes implementations of synchronized multibrain “computing.” Usually they can be found in the artistic domain. In this decade (2010–20), we see growing attention in this research area, partly because of the availability of affordable electroencephalographic (EEG) devices and partly because of the interest of human–computer interaction researchers in effective computing.