This work offers five sections that guide the reader through PHP4 from the basics to the advanced functions. The first section of the book teaches the fundamentals of PHP. Building upon what has been taught in the first section, sections two through four show how to apply that knowledge in order to interact with the user by creating and managing forms, cookies and authentication. It also teaches how to access databases and how to integrate system components, e-mail, LDAP, network sockets and much more. The final section of the book covers advanced functionality including how to debug and optimize scripts, maintain script securit, and extend PHP with API.