From the Preface to Just Send Me Word: A True Story of Love and Survival in the Gulag, by Orlando Figes:

Three old trunks had just been delivered. They were sitting in a doorway, blocking people’s way into the busy room where members of the public and historical researchers were received in the Moscow offices of Memorial. … Noticing my interest in the trunks, they told me they contained the biggest private archive given to Memorial in its twenty years of existence. It belonged to Lev and Svetlana Mishchenko, a couple who had met as students in the 1930s, only to be separated by the war of 1941-5 and Lev’s subsequent imprisonment in the Gulag. …
We opened up the largest of the trunks. I had never seen anything like it: several thousand letters tightly stacked in bundles tied with string and rubber bands, notebooks, diaries, documents and photographs. The most valuable section of the archive was in the third and smallest of the trunks, a brown plywood case with leather trim and three metal locks that clicked open easily. We couldn’t say how many letters it contained – we guessed perhaps 2,000 – only how much the case weighed (37 kilograms). They were all love letters Lev and Svetlana had exchanged while he was a prisoner in Pechora, one of Stalin’s most notorious labour camps in the far north of Russia. The first was by Svetlana in July 1946, the last by Lev in July 1954. They were writing to each other at least twice a week. This was by far the largest cache of Gulag letters ever found. But what made them so remarkable was not just their quantity; it was the fact that nobody had censored them. They were smuggled in and out of the labour camp by voluntary workers and officials who sympathized with Lev. Rumours about the smuggling of letters were part of the Gulag’s rich folklore but nobody had ever imagined an illegal postbag of this size. …
As I leafed through the letters, my excitement grew. Lev’s were rich in details of the labour camp. They were possibly the only major contemporary record of daily life in the Gulag that would ever come to light. Many memoirs of the labour camps by former prisoners had appeared, but nothing to compare with these uncensored letters, composed at the time inside the barbed-wire zone. Written to explain to his sole intended reader what he was going through, Lev’s letters became, over the years, increasingly revealing about conditions in the camp. Svetlana’s letters were meant to support him in the camp, to give him hope, but, as I soon realized, they also told the story of her own struggle to keep her love for him alive.
Perhaps 20 million people, mostly men, endured Stalin’s labour camps. Prisoners, on average, were allowed to write and receive letters once a month, but all their correspondence was censored. It was difficult to maintain an intimate connection when all communication was first read by the police. An eight- or ten-year sentence almost always meant the breakings of relationships: girlfriends, wives or husbands, whole families, were lost by prisoners. Lev and Svetlana were exceptional. Not only did they find a way to write and even meet illegally – an extraordinary breach of Gulag rules that invited severe punishment – but they kept every precious letter (putting them at even greater risk) as a record of their love story.
There turned out to be almost 1,500 letters in that smallest trunk. … These letters are the documentary basis of Just Send Me Word, which also draws from the rich archive in the other trunks, from extensive interviews with Lev and Svetlana, their relatives and their friends, from the writings of other prisoners in Pechora, from visits to the town and interviews with its inhabitants and from the archives of the labour camp itself.

Does the book live up to the promise of its preface? Yes. Yes, it does.