Imagine your broker offers you a can’t-miss investment. He doesn’t know much about the underlying asset—stock, bond, whatever. All he has is a chart that shows a breakout ahead, and urges you to jump now.

You would think he was nuts. Or into technical analysis. Or maybe both.

Technical analysis is one of the oldest activities on Wall Street. It remains as popular as ever today, thanks to sophisticated investing tools that have made retail traders the fastest-growing segment of chartists.

Since the early days of equity trading, investors have tried to find trading patterns that predict future movements—to discover a system. Untold riches have been lost on self-professed experts with unbeatable systems that got beat, and con men who profit off others’ hopes and dreams.

“What we need are soulless barometers, price indexes and averages to tell us where we are going and what we may expect,” William P. Hamilton, former Wall Street Journal editor, wrote in his 1922 tome on technical analysis, The Stock Market Barometer.

Hamilton subscribed to the Dow Theory, developed by Journal co-founder Charles H. Dow, the first systematic attempt to understand and anticipate price movement. More than a century later, Dow’s concepts remain the core of technical analysis.

Central among these concepts is that asset prices already reflect all available information—“everything everybody knows, hopes, believes [and] anticipates, with all that knowledge sifted down to…the bloodless verdict of the marketplace,” as Hamilton put it.

Known as the efficient market hypothesis, it basically says that fundamental analysis of a company’s earnings, management, etc., is a dead end. What can you know that everyone else doesn’t?

For Vanguard founder John Bogle and others, this was an argument for indexing, the triumph of passive investing over active.

To the chartists of technical analysis, the efficient market hypothesis only strengthened their belief in the immutable laws that govern the market, which they seek through moving averages, support and resistance levels, double tops, and Fibonacci retracements.

Today, technical analysis is used throughout Wall Street alongside fundamental research and, increasingly, artificial intelligence. You, too, can seek your fortune through the arcane world of Bollinger bands, candlestick charts, and Elliott waves, if you dare.

Before Dow elaborated on his theory, 14-year-old Jesse Livermore (1877-1940), a future Wall Street legend, was formulating his own investing ideas working the big board at Paine, Webber in Boston.

“I noticed that in advances as well as declines, stock prices were apt to show certain habits,” Livermore’s fictional counterpart says in Edwin Lefèvre’s best-selling roman à clef, Reminiscences of a Stock Operator. “It was not long before I was anticipating movements in prices.”

Livermore made and lost fortunes with his idiosyncratic approach to technical analysis. He sold short ahead of both the San Francisco earthquake of 1906 and the Wall Street crash of 1929, earning millions. Yet Livermore was deeply in debt on Thanksgiving Day, Nov. 28, 1940, when he took his own life.

Charles Dow (1851-1902) had been a working journalist for a decade when he joined Edward Jones and Charles Bergstresser in founding Dow Jones & Co. in 1882. With their first product, the Customers’ Afternoon Letter, they aimed to provide accurate, unbiased reporting on Wall Street, free from favoritism or bribery—imagine!

The Wall Street Journal was established in 1889, and Dow began outlining his theories in the Review & Outlook column.

“Nothing is more certain than that the market has three well defined movements which fit into each other,” Dow wrote on Jan. 4, 1902. The first movement constitutes daily variations, the second lasts 10 to 60 days, and the third “great swing” covers four to six years.

“It is necessary to think with reference to each of these periods in order to take advantage of opportunities,” he wrote. “If the main move is up, relapses are speculators’ opportunities, but if the main move is down, rallies furnish these opportunities.”

Dow emphasized the importance of trading volume as a momentum signal, bringing crowd psychology into analysis. He created the Dow Jones Industrial and Railroad averages to quantify market movements, and only when they moved in tandem was a “great swing” confirmed.

Dow never published his ideas in book form, nor did he ever refer to them as his “theory.” The term was coined in 1903 by disciple S.A. Nelson, in The ABC of Stock Speculation. He and Hamilton helped fully develop Dow’s concepts.

Some chartists look to an even earlier guru than Dow, 13th-century Italian mathematician Leonardo of Pisa, also known as Fibonacci. His great contribution to Western culture was the introduction of the Indo-Arabic numeral system. He also revealed what’s now known as the Fibonacci sequence, in which each number is equal to the two preceding it: 0, 1, 1, 2, 3, 5, 8, 13, 21, etc.

Intriguingly, dividing each number by the preceding one produces a ratio gradually approaching 1.618, known since ancient times as the golden ratio. The golden ratio appears throughout nature—in the spiral arrangements of leaves and shells, in the proportions of human bodies, in music, architecture, and, some say, financial markets.

Fibonacci retracement is a method of finding support and resistance levels—that is, where buy and sell orders are clustered. The commonly used levels, based on Fibonacci ratios, are 23.6%, 38.2%, 50%, and 61.8%, the last being another expression of the golden ratio.

Critics claim this is a self-fulfilling prophecy. If everyone is using Fibonacci ratios, then orders will naturally collect at those levels. The same with the 200-day moving average and other common signals, such as relative-strength indexes, which show when an asset is overbought or oversold. To proponents of technical analysis, those are simply additional inputs to consider.

For the individual investor, online investing platforms including Yahoo Finance, Bloomberg, and many others offer professional tools for technical research.

The charts don’t lie, according to believers. They simply need the proper interpretation. Then the mists will lift and the market’s secrets will be unveiled.

“Speculation,” as Livermore wrote in How to Trade in Stocks (1940), “is nothing more than anticipating coming movements.”

That’s the holy grail of technical analysis.