Riemmanian Geometry: Modern Introduction (2nd edition), Cambridge Studies in Advanced Mathematics 98, Cambridge University Press, Cambridge, 2006.
Isoperimetric Inequalities: Differential Geometric and Analytic Perspectives, Cambridge Tracts in Mathematics 145, Cambridge University Press, Cambridge, 2001. (pdf)
Riemmanian Geometry: A Modern Introduction, Cambridge Tracts in Mathematics 108, Cambridge University Press, Cambridge, 1994.
(with H.M. Farkas, eds) Differential Geometry and Complex Analysis: H.E. Rauch Memorial Volume, Springer Verlag, Berlin, 1985.
Eigenvalues in Riemannian Geometry (with chapter by B. Randol and appendix by J. Doziuk), Pure and Applied Mathematics 115, Academic Press, Orlando, 1984
Riemannan Symmetric Spaces of Rank One, Lecture Notes in Pure & Applied Mathematics 5, Marcel Dekker, New York, 1972.
The Laplacian on Riemannian Manifolds, Spectral Theory and Geometry, eds. E.B. Davies & Y. Safarov, London Math. Soc. Lecture Note Ser., 273 (1999), Cambridge U. Press, Cambridge, 30-75.
Topics in Isoperimetric Inequalities, Geometry, Spectral theorgy, Groups, and Dynamics, eds. M. Entov, Y. Pinchover, M. Sageev, Contemporary Mathematics, 387(2005), American Mathematical Society, Providence RI, 89-110.
to view additional published research.
Sagan in Silesia, in my own printing press, November 6, 1629:
"When the storm rages and the state is threatened by shipwreak, we can do nothing more noble than to lower the anchor of our peaceful studies into the ground of eternity
Johaness Kepler (quoted in Arthur Koestler, The Sleepwalkers, Grosset & Dunlap, New York 1963, p.422)