The growth of interest in distributed systems which address the business needs of companies, and which use network technology ? primarily the technology employed in the internet - has been dramatic.  This book describes the development of the new technologies that have emerged or have matured over recent years, such as web servers, CORBA, HTML, XML and Java.  It looks in particular at more challenging applications where major problems in performance and reliability need to be addressed. Using a ?bottom-up? approach, the book discusses client/servers and distributed development paradigms before moving on to more specific technologies that are examples of these concepts. The final part of the book covers advanced topics, such as internet security, concurrency, agents, and ubiquitous/mobile computing.