Two main gravity theories are:
General Relativity (A.Einstein, 1915)
Field Gravity (R.Feynman, 1961)
The best text-book on General Relativity (GR) is L.D. Landau
& E.M. Lifshitz, The classical theory of filds ,
Pergamon Press, N.Y. (1971).
The best book on Field Gravity (FG) is R.P. Feynman, F.B.Morinigo,
W.G. Wagner, Feynman Lectures on Gravitation, Ed. by Brien Hatfield
with Foreword by John Preskill and Kip Thorn, Perseus Books, USA (1995).
General discussion of geometrical (A.Einstein)
and field (R.Feynman) approaches for description of gravity see:
Yu.V.Baryshev, "Field Theory of Gravitation: Desire and Reality"
N.Straumann, "Reflection on Gravity"
General discussion of the equvalence principle and the paradox of radiation of
the accelerated charges see:
M.Pauri & M.Vallisneri, "Classical roots of the Unruh and Hawking effects"