I have in my hands two small exercise books: one has soft black covers cut out from an old school notebook; the other is bound in cardboard with black and yellow stripes, which was probably removed from a notepad my parents had once used to write down daily household expenses. My brother, Petr, made the two exercise books himself using old paper, and had them as diaries when he was a boy. For children such as Petr and I, a nice new exercise book from a stationery shop was completely out of reach.
Petr began writing the diaries when he was 13. In them, he records the years 1941-1942, when he, my mother, father and I were all living together at home in Prague. The diaries end two months before Petr was transported, aged 14, to Theresienstadt - a concentration camp where European Jews were taken en route to Auschwitz. He died in the gas chambers at Auschwitz two years later.
Both our parents were progressive people - Father was Jewish, Mother was not; they met at an Esperanto conference. Mother loved music; she had a beautiful voice and loved to sing arias to us. This was when we were little. After the war, the Holocaust, and Petr's tragic fate, she never sang again.
According to Nazi Nuremberg laws, children from mixed marriages were considered "First Degree Mischlings [mixed-breeds]". This meant Petr and I had to submit to the same restrictions as all other Jews (we wore a yellow star, we were thrown out of school, in streetcars we were allowed only in the last car if at all, etc), with one exception: we were deported to concentration camps only upon reaching 14.
This is why our parents had to give Petr away to the Germans when he turned 14 in 1942. They hoped the end of the war would come before I was taken away. But my time to leave came in 1944, and Petr and I were reunited for a short time: Petr had become by then a tall, thin, pale young man; his child's face gone. Later, Father was also deported to Theresienstadt (until then, he had been protected by having an Aryan wife) and Mother was alone.
In the end, everyone from my father's side of the family was killed during the Holocaust, except for my father, myself and one cousin.
The diaries Petr kept before all this horror - the ones I have before me now - only resurfaced in 2003, some 60 years after they were written, and under very unusual circumstances.
One of the astronauts on the space shuttle Columbia was an Israeli, Ilan Ramon, whose mother had survived Auschwitz. Ilan wanted to take a symbol of the Holocaust into space, and chose a copy of a drawing - Moon Landscape - that Petr had done as a child in Theresienstadt, and that had been found and put into the Holocaust museum in Jerusalem after the camp was liberated. On February 1 2003 - the day that would have been my brother's 75th birthday - Columbia disintegrated upon re-entering Earth's atmosphere. The tragedy was widely reported all over the world, and many of the reports mentioned my brother, and the drawing of the moon that an astronaut had taken on his final voyage.
Shortly afterwards, a man from Prague contacted the Holocaust museum, offering to sell what he believed to be Petr's diaries. The man had found them in the attic of a house he'd bought some years previously.
When I saw the diaries, I felt as if Petr hadn't actually died, but was alive somewhere in eternity. I knew instantly that they were genuine. I recognised Petr's handwriting and I remembered the events he was describing.
The diaries bought Petr alive again: the boy who was interested in everything. Not even the Nazis succeeded in stifling his desire to learn. When he was forced to leave school, he continued to educate himself, almost compulsively. In his diaries he often plans his activities a month ahead, and then analyses in detail how much of what he had intended had been successfully executed. Even after he was deported to the concentration camp, his passion for learning continued. Petr left notes (also now in the museum), titled "Plans and Reports", in the Theresienstadt dormitory, where in spite of everything he managed to spend two years full of creative work. This excerpt gives a flavour:
"May 1944 I finished the notes from Ceylon and bound them. I completed the preparatory work for the study of general education: I have read The System of Sociology by Chalupny, which contains a classification of sciences, and in this framework I have made a plan to learn a little about each science.
"I have read: Gwen Bristow: Deep Summer. Franck: Without a Penny Around the World, the detective novel The Silky Face, Chalupny: The System of Sociology, Wells: A Short History of the World, Pedagogical newsletter, Jiri Vaija: The Storytellers.
"I have drawn: The Brewery."
These "reports" fill me with very sad feelings. Petr read every book he could find - there was a library of books confiscated from Jews - and attended secret lectures given by experts from many disciplines who were also prisoners. In Theresienstadt, Petr found out about the horrors that can happen in human history, but it didn't make him change direction. One of the fruits of his unusual energy was Vedem (it translates as "We lead" or "We are winning"), a weekly magazine written by a group of young boys who inhabited House 1 in L417 in Theresienstadt. Petr edited this review, and wrote articles for it.
"They tore us unjustly away," he wrote in Vedem, "from the fertile ground of work, joy, and culture, which was supposed to nourish our youth. They do this for only one purpose - to destroy us not physically, but spiritually and morally. Will they succeed? Never! Deprived of our former sources of culture, we shall create new ones. Separated from the sources of our old happiness, we shall create a new and joyfully radiant life!"
I have read his Theresienstadt writings many times since his death, but the diaries are different. It is clear that Petr wrote them only for himself and that it never occurred to him that they could be read by someone else. In the pages of these two home-made books are absolutely truthful accounts about our family life, about Petr's friends and acquaintances, about the environment in which he grew up - and all this at a time when this environment is being destroyed, day after day, by Nazi abuse.
Petr presents all the facts without emotion, without worry, fear or hate. The fact he was thrown off a streetcar because he was a Jew is mentioned next to his report card consisting of all As.
Petr's diaries are also testimonies of the method used by the Nazis during the Holocaust. Everything appears to be functioning as usual. The Jews' freedom is being restricted only gradually, with new laws being announced with increasing regularity, listing items Jews have to give up, places they are not allowed to frequent, everything they are forbidden to do. More and more people are being called up for transports. Suddenly, a relative is leaving, one pupil or another, or a teacher is missing at school. People help each other pack suitcases for the journey, there is organised assistance for carrying luggage. But those who remain continue to live their seemingly normal lives. A teacher assigns the copying of 100 nouns as a punishment.
People do not understand. When Mr Mautner is called up for his transport, he goes to ask whether it isn't a mistake. Can this be possible? I am 50, and I have a heart defect! Those who are leaving for Poland have no idea that they will never see their carefully packed suitcases again. They do not suspect that maybe in as little as a week they will be gassed or burned or murdered in some other way.
My brother's diary is written in a calm style, but it changes in the last weeks and days, when he is expecting to be assigned to a transport. His notes are nervous, as if he didn't know what was happening to him and was unable to describe those days. Only in the diary he kept in Theresienstadt does he reveal the circumstances of his departure, after the fact, thus completing the diary he had started in his home-made notebooks in Prague.
"I was told to choose which of my toys I wanted to take," he writes. "I took a supply of paper, linoleum, small knives for cutting it, my unfinished novel. Daddy gave me his best shirts and a thick jacket, his ski boots ... Auntie Nada called me into the bedroom and implored me to be sensible, to stay away from big boys and bad girls. Then she untied the cuffs on my coat and inside each cuff near the sleeve she put a 100-mark bill.
"We took the tram to Veletrh ... It was dark. Daddy said goodbye to me. He kissed me several times and Auntie Nada gave me the last kiss. I was given a new number, 446. I handed over my suitcases in the optimistic hope that I would see them again someday."
So this is how Petr described his departure. A few years later, our father, Otto Ginz, wrote about saying goodbye:
"There were large sheds, where the victims, selected for transport to Theresienstadt, were told to assemble. I accompanied our Petr there. We had an earnest talk, but I avoided triggering sad thoughts in him, and we comforted each other by saying that we would both meet at home soon. We reached the point beyond which those accompanying the victims were not allowed to go. I pressed our Petr to me, we kissed, and Petr went inside. He turned around a few times, we waved to each other, and Petr disappeared in the gate. I turned away and at that moment a loud cry escaped my insides, more like a scream of pain. I don't know how I made it home."
This terrible moment of parting was the end of the two-year period recorded in Petr's diaries. The end of the last two years of our family life, before Petr was torn from it, before my mother stopped singing.
Toward the end of the diary, Petr's handwriting becomes different, disorganised, unsteady. I feel my own distress growing too, as I read each new page. He records the day that Uncle Milos leaves for the camp on June 14, the day that three teachers from his school left on June 27, his grandmother's departure on July 1; on July 28 Aunt Anda. From his handwriting, it is clear that Petr feels it is now his own turn.
His childhood has ended: the happy life with his parents and I; his schooling. Fourteen-year-old Petr begins two years in Theresienstadt where he makes new friends and explores new creative projects. Two years, which end with his journey to a gas chamber in Poland.
· This is an edited extract from Chava's introduction to The Diary of Petr Ginz, published by Atlantic Books at £16.99. To order a copy for £15.99 with free UK p&p go to theguardian.com/bookshop or call 0870 836 0875