Private letters are valuable historical sources but they also pose complicated ethical questions for the researcher: the more close to the present day they are, the more problematic they may appear. In this paper I will deal with the question of doing research on letters in a specific - Stalinist - context and with ethical issues related to such research, taking as my case study the correspondence of the Estonian poet Ilmi Kolla (1933-1954). She was very talented but died young, as a result of tuberculosis. She left behind numerous unpublished poems and letters to her mother and friends. In addition to their literary value, her manuscripts and correspondence disclose the hidden face of Stalinism and the way it manipulated people. The letters also reveal the intimate aspects of Ilmi Kolla's private life, e.g. about her femininity and sexuality, which have been silenced to this date. By focusing on Ilmi Kolla, I will discuss the use of private letters as a new way to write history. Particular attention will be paid to ethical problems involved in dealing with sensitive letter material. I will explore different options in using personal documents by asking what private letters reveal about the personal history of Ilmi Kolla and about the Stalinist era in Estonia. Letters will provide a more multilayered idea of the Stalinist era, in comparison with the habitually black-and-white image of totalitarian oppression and victimization. Private letters may elucidate the role of an individual in the processes of history, which may vary depending on the status and social position of the person, as the case of Ilmi Kolla demonstrates. Although her life was overshadowed by Stalinist cultural politics, she also made use of some of its benefits. Research based on letters may thus illuminate the hidden functioning mechanisms of the Soviet society. [ABSTRACT FROM AUTHOR]