Synopsis: Separation logic is a formal system for static reasoning about pointer-manipulating programs. Like Hoare logic, it uses assertions that serve as preconditions and postconditions of commands and functions. Unlike Hoare logic, its assertions model anti-aliasing via the disjointness of memory heaplets. Separation algebras serve as models of separation logic. We can define a calculus of different kinds of separation algebras, and operators on separation algebras. Permission shares allow reasoning about shared ownership of memory and other resources. In a first-order separation logic we can have predicates to describe the contents of memory, anti-aliasing of pointers, and simple (covariant) forms of recursive predicates. A simple case study of straight-line programs serves to illustrate the application of separation logic.