Question: Which family does the writer particularly discussed about their political activities in his book Dark Money?

Context articles: Veterans for a Strong America
Dark money
Jathika Nidahas Peramuna
Political activities of the Koch brothers
Nonpartisanism in the United States
Jane Mayer
Jack Oleck
Kenneth Vogel
Trevor Potter
Dark Money (book)

Veterans for a Strong America (VSA) is a conservative political action committee that describes itself as a "non-partisan action organization dedicated to educating the public, members of Congress and the Executive Branch about a strong national defense, robust foreign policy and building a military that is second to none."
 The group was founded by Joel Arends of Sioux Falls, South Dakota, who is also the chairman and sole staffer of the group.
 Arends is an attorney and political consultant in Sioux Falls, where the organization is based.
 He previously worked as the South Dakota field director for the 2000 Bush-Cheney campaign and as a consultant to the Americans for Prosperity group, affiliated with the Koch brothers.
 VSA has been described as a dark money group.
In the politics of the United States, dark money are funds given to nonprofit organizations—and include 501(c)(4) (social welfare) 501(c)(5) (unions) and 501(c)(6) (trade association) groups—that can receive unlimited donations from corporations, individuals, and unions, and spend funds to influence elections, but are not required to disclose their donors.
 Dark money first entered politics with Buckley v. Valeo (1976) when the supreme court laid out Eight Magic Words that define the difference between electioneering and issue advocacy.
The Jathika Nidahas Peramuna (JNP) or "National Freedom Front" (NFF) is a political party in Sri Lanka was formed by the ten JVP parliamentarians led by Wimal Weerawansa, the breakaway group of Janatha Vimukthi Peramuna or JVP, started their political activities on 14 May 2008.
 The party also achieved a historical milestone for the first time in country's history, a political party launched their official Web site (www.nffsrilanka.com) on the same date the political activities started.
The political activities of the Koch brothers include the financial and political influence of Charles G. and David H. Koch on United States politics.
 This influence is seen both directly and indirectly via various political and public policy organizations supported by the Koch brothers.
Nonpartisanism in the United States is organized under United States Internal Revenue Code (501(c)) that qualifies certain non-profit organizations for tax-exempt status because they refrain from engaging in certain prohibited political activities.
 The designation "nonpartisan" usually reflects a claim made by organizations about themselves, or by commentators, and not an official category per American law.
 Rather, certain types of nonprofit organizations are under varying requirements to refrain from election-related political activities, or may be taxed to the extent they engage in electoral politics, so the word affirms a legal requirement.
 In this context, "nonpartisan" means that the organization, by US tax law, is prohibited from supporting or opposing political candidates, parties, and in some cases other votes like propositions, directly or indirectly, but does not mean that the organization cannot take positions on political issues.
Jane Meredith Mayer (born 1955) is an American investigative journalist who has been a staff writer for "The New Yorker" since 1995.
 In recent years, she has written for that publication on money in politics, government prosecution of whistleblowers, the United States Predator drone program, Donald Trump's ghostwriter, and President Trump's financial backer, Robert Mercer.
 In 2016, Mayer's book "Dark Money", in which she investigated the history of the right-wing billionaire network centered around the Koch brothers, was published to critical acclaim.
Jack Oleck (March 1, 1914 – March 10, 1981) was an American novelist and comic book writer particularly known for his work in the horror genre.
Kenneth Vogel is an American journalist.
 He was the chief investigative reporter at "Politico", since its founding in 2007.
 In June 2017, he joined the Washington Bureau of "The New York Times" as a reporter covering conflict of interest issues, lobbying and money in politics.
 He is also the author of "Big Money: 2.5 Billion Dollars, One Suspicious Vehicle, and a Pimp–on the Trail of the Ultra-Rich Hijacking American Politics."
 Vogel's writing often focuses on money in politics.
 As part of his work, he focuses on political fundraising with particular emphasis on the political activities of the Koch brothers.
Trevor Potter is a lawyer, former commissioner (1991–1995) and chairman (1994) of the United States Federal Election Commission.
 He is the founder, President, and General Counsel of the Campaign Legal Center, a nonprofit organization which works in the areas of campaign finance and elections, political communication and government ethics.
 Potter is a vocal critic of unlimited corporate spending and dark money in politics allowed by the Citizens United v. FEC ruling.
Dark Money: The Hidden History of the Billionaires Behind the Rise of the Radical Right (2016) is a non-fiction book written by the American investigative journalist Jane Mayer, about a network of extremely wealthy conservative libertarians, foremost among them Charles and David Koch, who have together funded an array of organizations that work in tandem to influence academic institutions, think tanks, the courts, statehouses, Congress, and the American presidency for their own benefit.
 Mayer particularly discusses the Koch family and their political activities, along with Richard Mellon Scaife and John M. Olin who funded the American Legislative Exchange Council (ALEC), and the DeVos and Coors families.