One additional tool that's used partly for debugging and partly for optimization is the Profiler window, which is available only in Unity Pro by clicking on the Profiler tab in Window in the application menu, as shown in the following screenshot. In short, the profiler gives you a statistical top-down view of how time and workload is distributed across the different parts of your game and across system hardware components, such as the CPU and graphics card. Using profiler, you can determine, for example, how much time is consumed by camera rendering in the scene compared to physics calculations or to audio functionality, as well as to other categories. It lets you measure performance, compare numbers, and assess where performance can be improved. The profiler is not really a tool that alerts you to the presence of bugs in your code specifically. However, if you're experiencing performance problems in running the game, such as lags and freezes, then it could guide you to...