One of the things you should learn when working with the Delphi IDE is debugging an application. Along the way you will soon enough stumble upon bugs which needs debugging. You might already have thought of an alternative way to find out where that pesky bug is at and squash it. Using showmessage presenting the data you suspect is causing errors might help you with the simple bugs, but over time your applications will get more and more complex and showmessage will not be sufficient enough for tracing down your program errors. This is where Delphi's debugging tools come in.