%0 Journal Article %T F theory Vacua in Four Dimensions and Toric Threefolds %A Kenji Mohri %J Physics %D 1997 %I arXiv %R 10.1142/S0217751X99000415 %X We investigate D=4, N=1 F theory models realized by type IIB string compactification on toric threefolds. Massless spectra, gauge symmetries, phase transitions associated with divisor contractions and flops, and non-perturbative superpotentials are analyzed using elementary toric methods. %U http://arxiv.org/abs/hep-th/9701147v1