Driven by the emergence of promising Internet-of-Everything (IoE) applications ranging from extended reality and automated systems to the tactile Internet, 6G is expected to provide diverse services including, e.g., communication, computing, and sensing, as well as achieve more ambitious network performance than 5G. To meet the future demands of 6G, an innovative concept referred to as the smart radio environment has been recently proposed, which suggests that random and time-varying wireless channels can be dynamically controlled/reconfigured to enhance wireless communication performance, by leveraging digitally-controlled low-cost intelligent reflecting surface (IRS) or its various equivalents such as reconfigurable intelligent surface (RIS) and others. Besides communication, IRS can also be exploited to improve the computing and sensing performance of future 6G wireless networks. The aim of this special issue is to motivate innovative research on IRS for achieving green communication, computing, and sensing in future 6G wireless networks. The issue attracted 18 high-quality submissions from all over the world, among which 6 original contributions were eventually selected for publication. The special issue covers diverse applications of IRS and various design issues in IRS-aided wireless systems. The novelty and key contributions of these articles are summarized as follows.