The most useful thing to know before reading about Sri Lanka is that the civil war is the destination and not the whole subject, and that most books about it were written to win an argument still running. The order below reaches the fighting only after the colonial reorganisation that hardened modern ethnic categories and the post-independence politics that made Sinhala and Tamil nationalism mutually exclusive, because the war is close to unreadable without them.
The second thing: the end of the war in May 2009 is unresolved as a factual question. UN-linked estimates of civilian deaths in the final months range from roughly 7,000 to more than 40,000, and the Sri Lankan state disputes all of them. Four books on this list are grouped deliberately so that you see the spread rather than one number.
The island, and what colonial rule did to it
K. M. De Silva's A history of Sri Lanka is the standard single-volume history, from antiquity to the modern state, at just over 600 pages. It was also written from within Sinhalese scholarly institutions and is contested on that basis by some Tamil historians; treat it as the baseline you will later argue with. Nira Wickramasinghe's Sri Lanka in the Modern Age is the book that makes the rest intelligible — how nineteenth-century censuses, plantations and colonial ethnography hardened identities often presented as inherited intact from antiquity. If you read one book from this stage, read that one.
Two nationalisms, 1948 to 1983
S. A. Pakeman's Ceylon is a 1964 survey by a British academic who taught on the island, valuable now as a period document written before anyone knew what the state would become. The analytical core is two books by Stanley Tambiah, a Sri Lankan Tamil anthropologist arguing against the majoritarian consensus: Sri Lanka, catalogued under the bare title and written just after the July 1983 pogrom, on how majoritarian politics dismantled the institutions that might have contained the conflict; and Buddhism betrayed?, on political Buddhism and the sangha's role in Sinhala nationalism, which was banned in Sri Lanka. Read them in that order — the first sets up the second.
Inside the war
M. R. Narayan Swamy's Tigers of Lanka, from boys to guerrillas is the organisational history of how the LTTE grew from a handful of young men in Jaffna into an army with its own navy, and his Inside an elusive mind, Prabhakaran is the only serious attempt in English at a biography of the man who ran the movement for three decades. What they describe is not in dispute: the LTTE pioneered suicide bombing at scale, destroyed rival Tamil groups, recruited children, and killed Tamil civilians and politicians who disagreed with it.
The Broken palmyra is the book that refuses every available side. Written by dissident academics at Jaffna University, it documents abuses by the Sri Lankan forces, the Indian Peace Keeping Force and the LTTE alike, and colleagues of its authors were later murdered. It was written at real cost and it is the honest centre of the path.
2009 and the disputed ending
Read these four as one set. Gordon Weiss, the UN spokesman in Colombo during the final offensive, argues in The cage that the state's conduct amounted to mass atrocity, while being explicit that the LTTE held civilians as a shield; this is the book the government has attacked hardest. Still Counting The Dead Survivors Of Sri Lankas Hidden War — the catalogue runs the subtitle into the title — is survivor testimony gathered by the former BBC Colombo correspondent Frances Harrison, and is much closer to the ground. Ahmed Hashim's When counterinsurgency wins asks a different question, treating the state's victory as a military case study; it sits uncomfortably beside the other two, which is why it is included. Samanth Subramanian's This divided island travels the postwar country interviewing Sinhalese, Tamils and Muslims about what they did and what they now say, and is the best account of the aftermath.
Documented on both sides: the army shelled an area it had itself declared a no-fire zone, and the LTTE prevented civilians from leaving it. Not settled: the civilian death toll. No book here settles it, and a guide that gave you a single confident figure would be misleading you.
What the histories cannot reach
Two novels finish the sequence, doing evidential rather than decorative work. Shyam Selvadurai's Funny Boy is a Tamil boy's coming of age in Colombo ending inside the July 1983 riots. Michael Ondaatje's Anil's Ghost follows a forensic anthropologist identifying the disappeared; his refusal to assign blame drew sharp criticism from Tamil readers, which is worth knowing going in.
The whole sequence, with a study plan per stage, is the history of Sri Lanka reading path.