  For projective conifold transitions between Calabi-Yau threefolds $X$ and
$Y$, with $X$ close to $Y$ in the moduli, we show that the combined information
provided by the $A$ model (Gromov--Witten theory in all genera) and $B$ model
(variation of Hodge structures) on $X$, linked along the vanishing cycles,
determines the corresponding combined information on $Y$. Similar result holds
in the reverse direction when linked with the exceptional curves.
