  A method is described for solving relativistic quasi-potential equations in
configuration space. The Blankenbecler-Sugar-Logunov-Tavkhelidze and an
equal-time equation, both relativistic covariant two-body equations containing
the full Dirac structure of positive and negative energy states, are studied in
detail. These equations are solved for a system of two constituent quarks
interacting through a potential consisting of a one-gluon exchange part with
running coupling constant plus a linear confining potential which is mostly
scalar and partly vector, and the spectrum of all light and heavy mesons is
calculated.
