The Galactic Bulge can uniquely be studied from large samples of individual stars , and is therefore of prime importance for understanding the stellar population structure of bulges in general .
Here the observational evidence on the kinematics , chemical composition , and ages of Bulge stellar populations based on photometric and spectroscopic data is reviewed .
The bulk of Bulge stars are old and span a metallicity range - 1.5 \mathrel { \hbox { \raise 2.15 pt \hbox { $ < $ } \hbox to 0.0 pt { \lower 2.15 pt \hbox { $ \sim$% } } } } [ Fe/H ] \mathrel { \hbox { \raise 2.15 pt \hbox { $ < $ } \hbox to 0.0 pt { \lower 2.15 pt \hbox { $ \sim$% } } } } +0.5 .
Stellar populations and chemical properties suggest a star formation timescale below \sim 2 Gyr .
The overall Bulge is barred and follows cylindrical rotation , and the more metal-rich stars trace a Box/Peanut ( B/P ) structure .
Dynamical models demonstrate the different spatial and orbital distributions of metal-rich and metal-poor stars .
We discuss current Bulge formation scenarios based on dynamical , chemical , chemodynamical and cosmological models .
Despite impressive progress we do not yet have a successful fully self-consistent chemodynamical Bulge model in the cosmological framework , and we will also need more extensive chrono-chemical-kinematic 3D map of stars to better constrain such models .