Finally, we come to what can probably be appropriately described as the crux of the entire book. It is also the final chapter of the book; everything that has come before has been leading up to this. PHP was originally created by Rasmus Lerdorf for processing hypertext (HTML) on web servers (aka “the backend”). It was only natural that PHP’s feature set grew to include tools for dealing with HTML-adjacent tasks, such as interacting with the protocols for transferring hypertext (HTTP), connecting to databases, transferring files (FTP), or sending email (SMTP). In the very first chapter – Getting Started – we saw how PHP can be run via various server APIs (SAPIs) the majority of which involve some form of web server. PHP even has a limited server built in, though it exists purely for development purposes and is not to be used in any other context. PHP – standing first for Personal Homepage, then later PHP Hypertext Preprocessor – and the internet have grown together over the last twenty-plus years, and certainly the PHP of today (version 8.4) is a far cry from anything that came before version 5.