Status of the quark and spin contents of the proton is reviewed. The topics included are:1. The sea content of the proton2. EMC-SLAC data and the proton spin crisis3. Anomalous gluon effect in the parton model4. Anomalous gluon effect in the OPE approach5. Generalized U(1) Goldberger-Treiman relation6. Polarized parton distribution functions7. Experimental tests on sea- and gluon-spin effects