The Sherman Antitrust Act of 1890 is a groundbreaking piece of US federal legislation that acts as a cornerstone of American anti-trust policy. It is widely considered to be the first federal law in the nation that aimed to restrict the growth of monopolies by curbing unlawful business practices like price-fixing and predatory pricing.

The Act is named after Ohio Sen. John Sherman who proposed and passed it in 1890. It was the first instance of US legislation to regulate free market competition and interstate commerce. The Act makes monopolistic business practices and agreements illegal, and it is among the most important pieces of federal legislation to help safeguard free competition.

The Sherman Antitrust Act forbids any "trust" (as in an alliance of companies, created to illegally limit competition) as well as any "unreasonable" restraint of trade and commerce by an individual or business. It also sets prohibitions on price-fixing and predatory pricing and forbids the use of easily achievable monopolies to the detriment of consumers.

The Sherman Antitrust Act sets penalties for refusing to comply with the laws, including monetary fines and prison time. Companies found in violation of the Act are subject to civil antitrust suits, which may result in hefty fines, being broken up or dissolved, or in extreme cases, criminal charges. The fines can go above the value of assets generated by the illegal activities.

The Sherman Act also serves as a deterrent for businesses not to engage in such practices and to reject calls to collude. As a result, markets become more efficient, prices become more competitive, competition is strengthened, and consumers benefit.

The Sherman Act has also had a positive effect on American society. From young entrepreneurs developing innovative products to increased wages for workers, it has continually improved economic growth and competition. The Act has had many successes over the last 130 years, but it can still be amended or improved upon. For example, the Clayton Act of 1914 addresses some of the weaknesses of the Sherman Act and expands its scope. This includes limiting exclusive sales contracts, interlocking directorates, and mergers.

In conclusion, the Sherman Antitrust Act of 1890 embodies the values of fair enterprise and competition for the benefit of consumers, workers, and businesses. It is as relevant today as it was over a century ago and serves as an important part of the US Anti-trust laws, designed to promote free competition and a level playing field.