Strangeness in the proton and N ∗ ( 1535 )

The newest progress on the study of the strangeness in the proton and in the lowest negative parity nucleon excited state N * (1535) is reviewed. Implications on the internal quark structure of the proton, N * (1535) and other baryons are discussed. The diquark cluster picture for the 5-quark components in baryons gives a natural explanation not only to the empirical indications for a positive strangeness magnetic moment µ s and positive strangeness radius of the proton but also the longstanding mass-reverse problem of N * (1535), N * (1440) and Λ * (1405) resonances as well as the unusual decay pattern of the N * (1535) resonance. Evidence for possible existence of N * (1535)'s 1/2 − SU(3) nonet partners in this picture is pointed out, and suggestion is made to search for these 1/2 − hyperon excited states under the well known Σ * (1385), Λ * (1520) and Ξ * (1530) peaks in various reactions.