This video covers how to handle Command Line Parameters in your Delphi applications, with them you can make your applications more flexible giving them some initial state (such as "myprog.exe /SafeMode") or instructing them to perform some actions at start up ("myprog.exe /TakeOverWorld"). This video is about 14 minutes long and is available on YouTube.
This book will make you a faster Delphi developer, it doesn't matter if you are just starting out, or have been using Delphi since version 1, you will find all sorts of tips, tricks and hacks to boost your productivity.