We report on the improvement of our isobar models for elementary kaon photo- and electroproduction, γr , v+ N→ K+ Y, during the last two decades. Our effort started with the investigation of kaon photoproduction near threshold, followed by the construction of new models which were intended to explain all KΛ and KΣ data from threshold up to W≈ 3 GeV by using two approaches, i.e., the partial waves and the fully covariant isobar models. Both approaches yield nice agreement with the presently available experimental data. A number of applications of the models in nuclear and particle physics area are presented. We also discuss our effort to use the pure spin-3/2 and spin-5/2 propagators in meson scattering and meson photoproduction processes.