As a member of the workforce, you probably have two things that are more important to you than anything else, at least in a professional sense: Your truck and your toolbox. You take both of them with you wherever you go. This is true if you work in construction, plumbing, or many other industries. When you get Waterloo toolboxes, you have to consider how to secure them to the truck when you want to throw them in the back bed and go to work. You will not always have enough room in the cab.
Some toolboxes are built for this purpose. You will see that they are constructed to fit right across the bed, up against the cab, and they can be fastened in place. These are huge toolboxes that can be removed, though you usually will not move them around very much. They just protect the tools that you have to bring that are large enough to be moved on their own, such as circular saws.
For smaller toolboxes, you just need to get a set of straps. There should be four hooks in the corners of the bed that are made out of metal. They look like boat cleats. You can either wrap the straps around them or hook the metal end through the middle. Put the toolbox up against one wall of the bed, hook the strap to the cleats on both sides, and then tighten it with the handle to hold the box in place.