Abstract
In this article, we discuss the anomalous transport phenomena in nearly antiferromagnetic metals, like high-Tc cuprates, organic superconductors, and some heavy fermion systems. We also discuss the grand-Kadowaki-Woods relation in heavy fermion systems with general orbital degeneracy. Finally, we investigate the pairing mechanism and the gap structure in iron-pnictide superconductors in terms of the orbital-fluctuation theory based on the multiorbital Hubbard-Holstein model.