  We survey various U_A(1) problems and attempt to resolve the two puzzles
related to the eta mesons that have experimental verification. Specifically, we
first explore the Goldstone structure of the eta and eta' mesons in the context
of eta-eta' mixing using ideas based on QCD. Then we study the eta decays
eta->3pi0, eta'->3pi0 and eta'->eta pi pi. Finally we arrive at essentially the
same picture in the dynamical scheme based on consistently coupled
Schwinger-Dyson and Bethe-Salpeter integral equations. This chirally
well-behaved bound-state approach clarifies the distinction between the usual
axial-current decay constants and the gamma gamma decay constants in the
eta-eta' complex. Allowing for the effects of the SU(3) flavor symmetry
breaking in the quark-antiquark annihilation, leads to the improved eta-eta'
mass matrix.
