This book contains enough mnaterial for three complete courses of study. It provides an introduction to the world of logic, sets and relations. It explains the use of the Znotation in the specification of realistic systems. It shows how Z specifications may be refined to produce executable code; this is demonstrated in a selection of case studies. The essentials of specification, refinement and proof are covered, revealing techniques never previously published. Exercises, Solutions and set of Tranparencies are available via http://www.comlab.ox.ac.uk/usingz.html