In　this　paper,　a　quadruple　code　index　modulation　(QCIM)　technique　is　proposed　for　low-complexity　and　spectral-efficient　wireless　transmission.　The　proposed　QCIM　scheme　utilizes　quadruple　code　indices　in　addition　to　M-ary　phase　shift　keying　symbols　to　transmit　more　information　bits　compared　to　conventional　code　index　modulation　(CIM)　schemes.　To　recover　the　transmitted　information　bits,　we　propose　maximum　likelihood　detection　(MLD)　and　greedy　detection　(GD)　algorithms　for　the　proposed　QCIM,　with　the　GD　algorithm　offering　almost　the　same　bit　error　rate　(BER)　performance　to　the　MLD　algorithm　but　with　significantly　lower　system　complexity.　Additionally,　we　extend　QCIM　into　a　reconfigurable　intelligent　surface　(RIS)-assisted　QCIM　(RIS-QCIM)　system,　which　significantly　enhances　BER　performance　and　eliminates　the　need　for　channel　state　information　at　the　receiver.　Numerical　results　demonstrate　that　the　proposed　QCIM　and　RIS-QCIM　achieve　higher　spectral　efficiency　and　superior　BER　performance　in　contrast　to　benchmark　schemes.　　©　2015　IEEE.