The Netherlands Antilles was a country within the Kingdom of the Netherlands that dissolved in 2010.
These islands do not have that much in common. Three are rather small and English speaking and lie not far from the Virgin Islands. They are Saba, St. Eustatius and St Maarten. The latter is actually partly French.
The other three speak a Spanish/Portugese Creole known as Papiamento of Papiamentu (even on that they disagree). They are a bit bigger and lie just of the coast of Chavez' Venezuela. They are Aruba, Bonaire and Curacao. The latter one is the largest of the three.
Curacao was a way station in the triangular slave trade in which European goods were hauled from Holland to places like Ghana, there sold and exchanged for African "goods" (i.e. slaves) and these brought to the Americas and exchanged for American produce and hauled back to Holland. One reason for this peculiar but very profitable arrangement was that Holland itself did not welcome any slaves to be sold on its own soil. (They did welcome the rich slave traders though).
Because of this history Curacao is a predominantly black ("Creole") island, but Bonaire and Aruba have retained more of their original Native American ethnicity, and no the two do not always see eye to eye. This is one reason why Aruba insisted upon a "Status Aparte" and become a separate country within the Kingdom later on.
After the abolition of slavery the "West", i.e. the Dutch colonies in the Americas: the six islands and Suriname were largely forgotten in the Netherlands. All eyes went to the further conquest of the "Emerald Girdle" known today as Indonesia. The emergence of the oil industry did change that a little because Curacao became a major refinery site for Venezuela's oil for a while. The later closure of the Shell refineries on the island wreaked havoc on the island's economy.
After the Netherlands were finally forced to accept Indonesian independence in 1949 a big debate started within the country causing a generational rift between the defenders of the colonial idea and their children, who often hurled unspeakable accusations at their parents' heads. At least on one point they could agree: the last remaining bits of colonial empire needed to be made independent in a decent and responsible matter. This led to the Statute of the Kingdom on 1954 in which Suriname and the Netherlands Antilles were created as separate countries within the Kingdom, next to the Netherlands proper, in preparation for independence. It also led to the Netherlands proper pumping money into the new countries to prepare for independence. Suriname did become independent in 1975, although the way in which deserves a page of its own. Suffice it to say that it did not take long for the new country to follow so many other newly independent states into losing its democracy and seeing its economy wrecked.
The enthusiasm for total independence on the collection of six rather disparate islands disappeared almost entirely. The political class that emerged after the Statute was granted loved their cushy jobs as ministers and secretaries and they also liked spending money on creating cushy jobs for their friends and families. As the government of the Antilles resided on Curacao, those friends and families lived mostly on that particular island and the other islands did not see much of that stimulus. This is another reason that Aruba claimed its separate status as a country inside the Kingdom. Of course that created more ministers and secretaries, but at least the new country took care of its own finances rather successfully. The island developed a profitable tourist industry. The financial situation in the remaining five Netherlands Antilles became a bigger and bigger mess.
After the year 2000 a new generation had grown up in the Netherlands that had not lived through the demise of the colonial empire. They started to hurl accusations at their parents' head for wasting the taxpayers’ money on all these irresponsible ministers, secretaries and their friends and families. In addition the four smaller members of the Antilles started to ask themselves why they should not follow Aruba's example and claim Status Aparte as well. The Netherlands did not like the idea of even more ministers and secretaries, but in the end it was decided to abolish the Netherlands Antilles. Curacao and St. Maarten will get Status Aparte as a country, but Bonaire, St. Eustatius and Saba will be incorporated into the Netherlands proper as overseas communities. The debts will be paid by the Netherlands, but under condition that the local ministers can no longer make any debts.