The use of symmetries and conservation laws in the qualitative
description of dynamics has a long history going back to the founders of
classical mechanics. The focus of this work is a comprehensive and
self-contained presentation of the intimate connection between
symmetries, conservation laws, and reduction, treating the singular case
in detail. This Ferran Sunyer i Balaguer Prize-winning monograph is the
first self-contained and thorough presentation of the theory of
Hamiltonian reduction in the presence of singularities. It can serve as
a resource for graduate courses and seminars in symplectic and Poisson
geometry, mechanics, Lie theory, mathematical physics, and as a
comprehensive reference resource for researchers.