  The first year Wilkinson Microwave Anisotropy Probe data favors primordial
adiabatic fluctuation with a running spectral index with $\ns >1$ on a large
scale and $\ns <1$ on a smaller scale. The model building of inflation that
predicts perturbations with such a spectrum is a challenge, because most models
predict fluctuations with either $\ns >1$ (hybrid inflation) or $\ns <1$ (new,
chaotic, or topological inflation). We give a sensible particle physics model
in supergravity that accommodates the desired running of the spectral index
using double inflation.
