The last ten or fifteen years have seen a considerable growth of scholarly interest in Persian biographical dictionaries (i.e., tazkirahs), to an extent that it may now be possible to point to tazkirah studies as a recognized and active subfield of Persian literature studies. In English-language scholarship, this trend has been advanced by researchers such as Paul Losensky, Sunil Sharma, and Rajeev Kinra, to name a few. Despite the recent wave of publications and dissertations, however, there remain a number of fundamental questions about the tazkirah tradition. These works, after all, are collectively myriad and often individually massive, and they have not tended to receive serious attention on their own terms (with some exceptions, mostly in Persian). We still have a huge amount of ground to cover. One of the major questions surrounding tazkirahs, particularly from earlier periods, is how they were researched and written. The authors only occasionally mention their sources or their writing processes, and what statements we find tend to be vague. I would like to discuss an atypical case: a tazkirah titled "Khayr al-bayan," written by Malik Shah Husayn Sistani (b. 978/1571) in multiple drafts between 1017/1608-9 and 1036/1627, mostly or entirely during stays in Harat. (The "Khayr al-bayan" has not yet been edited for publication; my paper relies on the earliest extant manuscript, held at the British Library.) Throughout this work, Shah Husayn includes bits of information about the process of authoring it. We know when and why he started to write his tazkirah; on what dates he completed some individual sections; where, and with whose help, he carried out a round of extensive revisions in 1035/1625-6; and more. In my paper I will attempt to piece together the story of the composition of the "Khayr al-bayan." While we cannot assume that all tazkirahs were written in similar ways, looking at one unusually detailed example may at least serve to open a discussion. And it is important for us to ask more questions about how tazkirah authors carried out their work, if we hope to make nuanced use of this body of sources.