The Pseudogap Phenomenon in High-T$\text{}_{c}$ Superconductors

We review the possible mechanisms leading up to the phenomenon of a pseudogap which characterizes the normal-state properties of high-T$\text{}_{c}$ superconductors. We suggest that this pseudogap is not due to superconducting phase fluctuations and hence is not related to a crossover between a BCS state of Cooper pairs and a Bose-Einstein condensation of local pairs. We rather argue that it is due to uncorrelated pairing which is already manifest in the local electronic structure and accessible by photoemission and tunneling experiments