This book is primarily concerned with the study of cohomology theories of general topological spaces with "general coefficient systems." Sheaves play
several roles in this study. For example, they provide a suitable notion of
"general coefficient systems." Moreover, they furnish us with a common
method of defining various cohomology theories and of comparison between
different cohomology theories.
The parts of the theory of sheaves covered here are those areas
important to algebraic topology. Sheaf theory is also important in other fields of
mathematics, notably algebraic geometry, but that is outside the scope of
the present book. Thus a more descriptive title for this book might have
been Algebraic Topology from the Point of View of Sheaf Theory.