An introduction to operating systems, covering processes, states of processes, synchronization, programming methods of synchronization, main memory, secondary storage and file systems. Although the book is short, it covers all the essentials and opens up synchronization by introducing a metaphor: producer--consumer that other authors have employed. The difference is that the concept is presented without the programming normally involved with the concept. The thinking is that using a warehouse, the size of which is the shared variable in synchronization terms, without the programming will aid in understanding to this difficult concept. The book also covers main memory, secondary storage with file systems, and concludes with a brief discussion of the client-server paradigm and the way in which client-server impacts the design of the World-Wide Web.