The paper is intended for newcomers as a roadmap to the more important list of concepts of the wireless communications area and surveys, with a bird's eye view, the vast area of wireless communication systems and the developments that led to 3G wireless standards such as UMTS and IMT2000, the latest multinationally negotiated 3G standard. Due to the span of the area and the size of this paper, the paper by necessity does not go into any depth of subject, but rather organizes the most relevant topics in wireless applications, to serve as a guide to delve into more depth, in a logical manner, into the various subjects as could be presented in an undergraduate/graduate course on wireless communications systems. The topics were selected from a review of a representative selection of recent textbooks and articles, written by workers/researchers in the field of wireless communication technologies, from academia and industry. We first present the types of applications and services available over IMT-2000, and the most important organizations involved in the wireless standards evolution from 1G to 3G systems. Other topics which are "overflows" are the issue of wireless capacity and ways to resolve its scarcity, from access methods to network intelligence, key enabling technologies for the design of 3G/4G systems, wireless network architecture of various sizes from PAN (personal area networks) to WAN (wide area networks), and the issue of network interworking. Indeed, interworking of various wireless networks standards and topologies to provide a full set of features such as broadband, adaptable or reconfigurable, all-IP connectivity, to form an ad-hoc wireless network will be at the heart of the B3G/4G systems.