References for the courses:

Groups as metric spaces:

Hyperbolic groups:

Gromov notes on hyperbolic grops:

Hyperbolic geometry:

Lyndon, Roger C.Schupp, Paul E. Combinatorial group theory. Reprint of the 1977 edition. Classics in Mathematics. Springer-Verlag, Berlin, 2001.

Ollivier, Yann(F-ENSLY-PM) A January 2005 invitation to random groups.  Ensaios Matemáticos [Mathematical Surveys], 10. Sociedade Brasileira de Matemática, Rio de Janeiro,2005.

Bridson, M and Haefliger, A., Metric Spaces of Nonpositive Curvature.

Meier, John,

Groups, Graphs, and Trees: An Intro to Geometry of Infinite Groups.

Tomkowicz, Gr. and Wagon, S., The Banach-Tarski Paradox (Encyclopedia of Mathematics and its Applications) 2nd Edition.

de la Harpe, P., Geometric Group Theory.