The economic policies of Ronald Reagan, often labeled "Reaganomics" were based on the principle of limited government. They included reducing taxation, limiting government spending, reducing inflation, and curbing government regulation. All these policies were intended to create a positive climate in which businesses could grow quickly and entrepreneurs could build wealth. Advocates of these policies argued that creating such an environment would eventually benefit everyone in society, since the wealth created would fuel the economy and provide more jobs. This idea became known as "trickle-down" economics, though its proponents did not use the label themselves.
The overall effects of Reaganomics are still a matter for debate, but it is generally agreed that the trickle-down theory has been a failure. The attached analysis from the Pew Research Center shows how economic inequality has increased in the last forty years (the data actually begins before this, but Reaganomics had no effect on the trend). The data shows that Reagan's policies actually allowed the wealthy to build and hoard immense fortunes, and that this trend continued under George H. W. Bush and, for that matter, under Clinton and subsequent presidents. As with any government policy, there are some metrics by which Reaganomics can be called a success. It reduced GDP, and created a great deal of wealth in the upper echelons of society. However, the policy did nothing for the poor and led to a sharp increase in the national debt.