The seminal 1970 Moscow thesis of Grigoriy A. Margulis, published for
the first time. Entitled "On Some Aspects of the Theory of Anosov
Systems", it uses ergodic theoretic techniques to study the distribution
of periodic orbits of Anosov flows. The thesis introduces the "Margulis
measure" and uses it to obtain a precise asymptotic formula for counting
periodic orbits. This has an immediate application to counting closed
geodesics on negatively curved manifolds. The thesis also contains
asymptotic formulas for the number of lattice points on universal
coverings of compact manifolds of negative curvature.
The thesis is complemented by a survey by Richard Sharp, discussing more
recent developments in the theory of periodic orbits for hyperbolic
flows, including the results obtained in the light of Dolgopyat's
breakthroughs on bounding transfer operators and rates of mixing.