In modern wireless communication systems, multiuser detection (MUD) is a good approach to achieve the highly reliable data transmissions. In the area of error control coding, the Chase algorithm, which takes advantage of the different reliabilities of the received symbols and focuses on correcting the error in the weakest symbols, can achieve a near maximum-likelihood (ML) performance and with significant complexity reduction. This book discusses the applications of the Chase algorithm in multiuser detection and proposes some novel detetors for the single-input single-output (SISO) and multiple-input multiple-output (MIMO) code division multiple access (CDMA) systems. In the SISO-CDMA systems, the proposed multiuser detector is developed from the multistage parallel interference cancellation (PIC) detector. In the MIMO-CDMA systems, the proposed detector is based on the layered space-time multiuser detector (LAST-MUD). Both of them can achieve higher performance and lower complexity compared to the previous developed multiuser detectors. This book can be used as a reference for engineers, researchers and students working in the field of wireless communications.