To operate future generation multimedia communications systems high data rate transmission needs to be guaranteed with a high quality of service. For instance, the third generation cellular mobile systems should offer a high data rate up to 2 Mbit/s for video, audio, speech and data transmission. The important challenge for these cellular systems will be the choice of an appropriate multiple access scheme. The advantages of the spread spectrum technique are: High immunity against multipath distortion, no need for frequency planning, high flexibility and easier variable rate transmission etc. On the other hand, the technique of multi-carrier transmission has recently been receiving wide interest for high data rate applications. The advantages of multi-carrier transmission are the robustness in the case of frequency selective fading channels, in particular the reduced signal processing complexity by equalization in the frequency domain, and in the capability of narrow-band interference rejection. The advantages and success of multi-carrier (MC) modulation and the spread spectrum (SS) technique has led to the combination of MCM with SS, known as multi-carrier spread-spectrum (MC-SS) for cellular systems. This combination, benefits from the advantages of both schemes: Higher flexibility, higher spectral efficiency, simpler detection techniques, narrow band interference rejection capability, etc. Multicarrier-Spread-Spectrum comprises a collection of papers which collectively provide a state-of-the-art overview of this emerging multiple access scheme. It will be a valuable reference for all researchers and practitioners working on the area of wireless communications and networking.