Wireless and sensorless sensing seeks breakthroughs in the contradiction between the limitation of WiFi and the growing demand for environment perception in daily life, seeks a balance between low cost and high accuracy, explores solutions via frequency diversity and spatial diversity, and creates applications that are previously infeasible in wireless communications and mobilecomputing.Weenvisiontechnologicaladvances would boost the capability of wireless sensing to finer granularity and higher sensitivity, which will in turn fostervariousnewapplications.Thisarticleonlyserves as an introduction on the concept of wireless and sensorless sensing, and we refer interested readers to the corresponding references for in-depth information. IfweconsiderWiFiasasidesensor,thenWiFi-based sensorlesssensingcanberegardedasoneoftheworld’s largest wireless sensor networks, spreading over office buildings, shopping malls, other public places and homes, and silently watching the activities of humans therein. Living inside such a network, every individual in the physical world has been bestowed with unique being in the digital world. So the next time you want a secret meeting, after shutting the doors, pulling down thecurtains,andevencheckingforwiretapsbeneaththe table, do not forget to turn off the WiFi!