Lèse-majesté - under which anyone who "defames, insults or threatens" the King, Queen, heir to the throne, or regent can be prosecuted - is Thailand's most controversial law. It is strictly enforced and broadly interpreted, and carries a social stigma in addition to a long jail sentence (three to fifteen years per offence). Bail is rarely granted in lèse-majesté cases, trials are heard in camera, in military courts, and there is no right of appeal. In a society in which kings are regarded as semi-divine, critics of the law are demonised as traitors and anti-monarchists.
Unsurprisingly, very little has been written about the history or legitimacy of the lèse-majesté law, and Truth On Trial In Thailand, by David Streckfuss, is the only full-length study of the subject. (A book published this year, ห้องเช่าหมายเลข 112, profiles lèse-majesté offenders, though it doesn't analyse the law itself. Streckfuss cites Borwornsak Uwanno's 2009 op-ed, written in defence of the law, as "the longest piece ever written in English (and probably Thai) by a Thai on the subject".)
Truth On Trial In Thailand: Defamation, Treason, & Lèse-majesté was first published in 2011. With 100 pages of notes, this is a comprehensive and authoritative study of Thailand's defamation and lèse-majesté laws. It's part of the Rethinking Southeast Asia series, edited by Duncan McCargo, who wrote a widely-cited paper on Thailand's patronage system (in The Pacific Review, 2005): "Thai politics are best understood in terms of political networks. The leading network of the period 1973-2001 was centred on the palace, and is here termed 'network monarchy'."
Streckfuss addresses the central paradox of lèse-majesté: "The difficulty for defenders of the law is to explain how the institution of Thai monarchy could be so utterly loved if it required the most repressive lese-majeste law the modern world has known." He also challenges the justifications used to defend the law, including exceptionalism ("a conceit about the uniqueness of all things Thai... understandable only to Thai") and national unity ("The obvious answer to the question of the incessant calls to Thai unity is that... no such unity ever existed and that even the appearance of unity has come at a terrible cost").
He also notes the increasingly flexible interpretation of the law, a tendency that has continued since the book was published: "A fairly consistent trend from lese-majeste cases can be discerned, from cases that referred personally to the king, queen, and heir-apparent, to cases where there was... only the most tenuous connection to the monarchy." The book even quotes some passages that fell foul of the law, such as a 23rd December 1981 Wall Street Journal article.