Toolkits implement a set of user interface features or application environments such as menus, buttons or scroll bars (referred to as widgets).
They allow applications to manipulate these features using object-oriented techniques.
X usually has two levels of toolkits above X
X Toolkit Intrinsics or Xt Intrinsics are a toolkit that allow programmers to create and use new widgets.
If we use widgets properly it will simplify the X programming process and also help preserve the look and feel of the application which should make it easier to use.
We will have to call some Xt functions when writing Motif programs since Motif is built upon Xt and thus needs to use Xt. We do not however need to fully understand the workings of Xt as Motif takes care of most things for us.