Ferengi
Physiology

Ferengi are a humanoid species with orange-brown skin, blue nails, enlarged skulls, wrinkled noses and sharp teeth. They have a unique four-lobed brain that is resistant to most telepathic probing. They are renowned for their large outer ears, which grant them exceptional hearing but can also make them susceptible to ear infections. Their physiology is similar to that of the Dopterians, who are distant relatives of the Ferengi.
Their most striking features are their large lobes. Those are sensitive to profit opportunities and sexual arousal. The term "lobeling" refers to a young Ferengi, showing the importance of lobes in their culture.
Ferengi are generally hairless, though some develop facial stubble or ear hair with age. They have higher blood pressure than that of Humans, and their yellow blood contains a type of cells called pyrocytes which also occurs in Kazon blood. These cells cause a severe allergic reaction when they come into contact with human skin.
Their lifespan often exceeds 100 years. When startled or distressed, a Ferengi might emit a high-pitched scream or hiss.
The typical Ferengi diet consists mostly of insects and other invertebrates, but they also eat marine species like fish or squid.
History
The Ferengi Alliance, led by the Grand Nagus, is the first political and economic entity of the Ferengi people. It focuses on commerce and profit, while the Ferengi Commerce Authority (FCA) controls business practices and trade regulations. His power is supported by the Ferengi Bill of Opportunities and the Rules of Acquisition.
Liquidators, governed by the Board of Liquidators are agents of the FCA.
The Ferengi generally avoid direct involvement in galactic politics. However, as they prioritize business opportunities, they will often engage with whoever is willing to trade with them. Since Ferengi businesses are generally run independently - on certain occasions they even turn to piracy and theft - the Ferengi Alliance is not directly involved in those questionable deals.
The Ferengi Alliance was created some 10,000 years ago by Gint, the first Grand Nagus, who also compiled the Rules of Acquisition.
The Alliance’s chief legal document is the Bill of Opportunities, which secures the rights of the citizens to pursue profit.
A temporal incident nearly led the Ferengi to create a first contact situation with Humans in 1947. After purchasing warp drive technology, the Ferengi once again encountered Humans in 2151, but there too no contact was made. Their first official contact with the Federation occurred in 2364. Despite sporadic skirmishes, they have maintained a level of diplomatic relations with the Federation.
Upon the (re-)discovery of the Bajoran wormhole to the Gamma Quadrant in 2369, the Ferengi Alliance (under Grand Nagus Zek) was the first Alpha Quadrant power to learn of the existence of the Dominion, via its relentless pursuit of new business opportunities beyond the wormhole.
In its earliest, forgotten phase, Ferengi society revolved around generosity. This trait waned when early tribes began trading and bartering, leading to a culture increasingly driven by greed. This is seen as the most effective way to make profits and gain technology. To quote Quark, "There is nothing beyond greed. Greed is the purest, most noble of emotions."
This extreme pursuit of profit, embodied in the 285 Rules of Acquisition, allowed the Ferengi to avoid slavery and genocide of their race. And yet, this myopic focus on material gain overshadowed their mistreatment of Ferengi women, who were seen as property and historically not afforded the same rights to pursue their own material betterment.
However, over time, starting with the action of Ishka (Quark's mother) and Ferenginar's ultimate leader, Grand Nagus Zek, the attitude toward women began to change. It nonetheless took the nomination of Rom (Quark's brother) in 2375 as a Grand Nagus, for those positive reforms to expand.
The Alliance’s initial relations with the Federation were hostile, however most of the negative encounters were with Ferengi pirates and independent operators, allowing the Alliance to feign denial of claims for any damages incurred. A policy of neutrality was for a long time the primary diplomatic position of the Ferengi Alliance with all other interstellar powers; practically this has meant that, with a bit of investigation, Ferengi financers and arms suppliers can be found on both sides in any given conflict. The Alliance has been known to have had trade connections with the Breen, the Orion Syndicate, and with the Cardassians (among others).
Key worlds in or near Ferengi space include Clarius, Irtok, Lapus IV, and Volchok Prime.
Culture
The Ferengi have a five-step process for acquiring wealth (infatuation, justification, appropriation, obsession, and resale) and they admire Earth's Wall Street.
Although the Ferengi are widely known for their ruthless habit when it comes to appropriating technologies from other species, their focus on profit led to inventions like holosuites and synthehol. While most Ferengi were driven by profit, some individuals had different motivations, like Leck's desire for excitement.
Despite their profit-based culture, Ferengi also valued family and can also be influenced by other pursuits.
Ferengi have historically been an intensely patriarchal society, where the most financially successful sons ascended the hierarchy, and where their female counterparts were not permitted to own property or even to wear clothing. Enterprising female Ferengi, none-the-less, often were able to get around restrictions and leverage influence, often by undermining or manipulating feckless males. In recent decades, much of Ferenginar’s gender discrimination has been undergoing a cultural revolution, especially as Ferengi overall become interested in doubling the pool of labor competition on the one hand, and in chasing after the spending of females entering the markets on the other hand.
The official currency of Ferenginar is Gold Pressed Latinum, but the mint and coinage can be various. Ferengi will often deal in other currencies (like Federation credits) and mediums of exchange depending on what markets they might expect to be able to exchange them in.
Philosophy
The Rules of Acquisition
Essentially a collection of Ferengi wisdom, The Book of Acquisition provides the keen businessman with advice to stake his fortune by. Ferengi lobelings are taught to read and copy from the rules of Acquisition and they are often found inscribed in key places throughout Ferengi homes and businesses. Some versions may state some of the rules slightly differently, or claim additional rules that have not been canonized. But it’s generally agreed that there are 285 of them. Give or take. (see: The Rules of Acquisition)
The Great Material Continuum (aka The Great River)
In the interstellar perspective of the Ferengi, each world is a place with too much of one resource and a demand for something it has too little of. The Great Material Continuum is a driving force that tries to meet demands by rewarding the self interest of the individual who opens and supplies the markets for wanted goods or services. Such an individual is said to be navigating the Great River, interpreting the needs between peoples, and collecting a profit along the way.
The principles of the Great Continuum are valued as a central pillar of societal virtue, and taught to Ferengi lobelings even before their ears grow all the way out.
The Divine Treasury of the Blessed Exchequer
Although a significant minority of Ferengi question the old faith, wealth accumulated in this life is believed by the most faithful of Ferengi to carry over to the next life on his eternal balance sheet, and to grant him favor with the Registrar of the Divine Treasury, in order to be ushered to meet the Blessed Exchequer, and to bid accordingly on the choicest of afterlives, as overseen by the Celestial Auctioneers.
sources:
Star Trek Adventures: Core Rulebook, pg325-326