JSP (Java Server Pages) allow Java code and special tags to be embedded in HTML files. This allows dynamic content to be generated for each user. JSP pages combine static markup with dynamic scripting elements. The JSP engine processes the pages on the server, converting them into servlets that generate HTML responses. Key benefits of JSP include easy maintenance, high performance, and platform independence since it is built on Java. Common JSP tags include directives, declarations, scriptlets, expressions, and actions. Directives provide instructions to the web container, while other tags allow embedding Java code and logic within HTML pages.