This chapter introduces key concepts about the internet and web development. It describes the evolution of the internet from the removal of commercial restrictions in the 1990s. It also explains standards bodies that coordinate internet protocols and addresses. The chapter outlines internet infrastructure, including clients, servers, and protocols like HTTP, TCP/IP, and domain name systems. It introduces markup languages like HTML, XHTML, and HTML5 that form the building blocks of web pages. Finally, it discusses popular uses of the internet like e-commerce, blogs, and social media.