  We present a comprehensive study of primordial fluctuations generated from
G-inflation, in which the inflaton Lagrangian is of the form $K(\phi,
X)-G(\phi, X)\Box\phi$ with $X=-(\partial\phi)^2/2$. The Lagrangian still gives
rise to second-order gravitational and scalar field equations, and thus offers
a more generic class of single-field inflation than ever studied, with a richer
phenomenology. We compute the power spectrum and the bispectrum, and clarify
how the non-Gaussian amplitude depends upon parameters such as the sound speed.
In so doing we try to keep as great generality as possible, allowing for non
slow-roll and deviation from the exact scale-invariance.
