  We introduce a new way of reconstructing the equation of state of a
thermodynamic system near a second order critical point from a finite set of
Taylor coefficients computed away from the critical point. We focus on the
Ising universality class (${\mathbb Z}_2$ symmetry) and show that in the
crossover region of the phase diagram it is possible to efficiently extract the
location of the nearest thermodynamic singularity, the Lee-Yang edge
singularity, from which one can (i) determine the location of the critical
point, (ii) constrain the non-universal parameters that maps the equation of
state to that of the Ising model in the scaling regime, and (iii) numerically
evaluate the equation of state in the vicinity of the critical point. This is
done by using a combination of Pad\'e resummation and conformal maps. We
explicitly demonstrate these ideas in the celebrated Gross-Neveu model.
