Answer the question at the end by quoting:

Horace Mann (May 4, 1796 - August 2, 1859) was an American educational reformer and Whig politician dedicated to promoting public education. A central theme of his life was that "it is the law of our nature to desire happiness. This law is not local, but universal; not temporary, but eternal. It is not a law to be proved by exceptions, for it knows no exception."
As the Old Deluder Satan Act and other Massachusetts School Laws attest, early education even under state control in Massachusetts had a clear religious intent. However, by the time of Mann's leadership in education, various developments (including a vibrant populist Protestant faith and increased religious diversity) fostered a secular school system with a religiously passive stance. While Mann affirmed that "our Public Schools are not Theological Seminaries" and that they were "debarred by law from inculcating the peculiar and distinctive doctrines of any one religious denomination amongst us ... or all that is essential to religion or to salvation," he assured those who objected to this secular nature that "our system earnestly inculcates all Christian morals; it founds its morals on the basis of religion; it welcomes the religion of the Bible; and, in receiving the Bible, it allows it to do what it is allowed to do in no other system--to speak for itself. But here it stops, not because it claims to have compassed all truth; but because it disclaims to act as an umpire between hostile religious opinions." Mann stated that this position resulted in a near-universal use of the Bible in the schools of Massachusetts and that this served as an argument against the assertion by some that Christianity was excluded from his schools, or that they were anti-Christian. Mann also once stated that "it may not be easy theoretically, to draw the line between those views of religious truth and of Christian faith which is common to all, and may, therefore, with propriety be inculcated in schools, and those which, being peculiar to individual sects, are therefore by law excluded; still it is believed that no practical difficulty occurs in the conduct of our schools in this regard." Rather than sanctioning a particular church as was often the norm in many states, the Legislature proscribed books "calculated to favor the tenets of any particular set of Christians.

Was Mann well known to a lot of people?

Answer the question at the end by quoting:

Vladimir Tismaneanu (Romanian pronunciation: [vladi'mir tism@'neanu]; born July 4, 1951) is a Romanian and American political scientist, political analyst, sociologist, and professor at the University of Maryland, College Park. A specialist in political systems and comparative politics, he is director of the University of Maryland's Center for the Study of Post-Communist Societies, having served as chairman of the editorial committee (2004-2008) and editor (1998-2004) of the East European Politics and Societies academic review. Over the years, Tismaneanu has been a contributor to several periodicals, including Studia Politica, Journal of Democracy, Sfera Politicii, Revista 22, Evenimentul Zilei, Idei in Dialog and Cotidianul. He has also worked with the international radio stations Radio Free Europe and Deutsche Welle, and authored programs for the Romanian Television Company.
Outside the realms of history, political science and political analysis, Vladimir Tismaneanu is a noted author of memoirs. This part of his work is centered on the volume Ghilotina de scrum ("The Ashen Guillotine"), also written on the basis of interviews with Mihaies. The book offers an account of his complicating relationship with Leonte Tismaneanu, postulating a difference between the everyday father, who has earned his son's admiration for being marginalized by his political adversaries, and a "political father", whose attitudes and public actions are rejected by Vladimir Tismaneanu. This approach earned praise from two influential intellectual figures of the Romanian diaspora, critics Monica Lovinescu and Virgil Ierunca, whose letter to the author read: "the distances you take from your own background are of most-rare authenticity and tact. You accomplish a radical break, being at the same time participative, negating things only after you have understood them, being dissociated from both roles of judge and defense counsel." Cioroianu also notes: "He is not the only son of (relatively) well-known communists; but he is one of the few to have reached the level of detachment needed in order to X-ray, in a cold and precise way, a political system. Does this seem easy to you? I do not know how many of us would be capable of introspecting with such lucidity our own parents' utopias, phantasms and disappointments". The historian opposes Tismaneanu's approach to that of Petre Roman, Romania-s first post-1989 Premier, whose attempts at discussing the public image of his father, the communist politico Valter Roman, are argued by Cioroianu to have "failed". Tismaneanu has contributed the screenplay for Dinu Tanase's documentary film Condamnati la fericire ("Sentenced to Happiness"), released in 1992. With Octavian Serban, he has also authored a series about Communist Romania, which was showcased by the Romanian Television Company.

Was his book successful?
This approach earned praise from two influential intellectual figures of the Romanian diaspora, critics Monica Lovinescu and Virgil Ierunca,