We gratefully acknowledge BT PLC., NEC, Ricoh, and the Media Lab's Things That Think consortium for their support of this research. We would like to acknowledge Thad Starner for the design of the base wearable system and contributing to the ideas of the Affective CD player. Frank Dabek helped create a prototype of the Affective CD player. Rob Gruhl, Smriti Banthia, Katherine McCoy, and Frank Dabek helped write software integrating the sensing hardware into the unix environment. Peter Chien, Grant Gould, and Kaechy Chen assisted in the development of wireless skin conductance and respiration sensors. The ideas of the safety net and of adapting music while jogging arose in conversations with Steve Mann.