  We identify the Riemann Xi function as the Baker-Akhiezer function for a
(p,1) two matrix model as p goes to infinity. We solve the two matrix model
using biorthogonal polynomials and study the zeros of the polynomials in the
double scaling limit as N goes to infinity. We find zeros off the critical line
at finite N which possibly go to infinity as N goes to infinity. We study other
Baker-Akhiezer functions whose zeros are known to be on a critical line using
the two matrix model technique and find the zeros on the critical line in those
cases. We study other L-functions using the two matrix model and compare the
biorthogonal method with other approaches to the two matrix model such as the
master matrix approach and saddle point method. In cases where there are zeros
off the critical line the master matrix approach encounters an obstruction to
the solution to a quenched master matrix.
