There is a peculiar branch of scholarship devoted to books that no longer exist. Its practitioners work almost entirely from citation. A lost work is reconstructed from the quotations of those who read it, the refutations of those who disliked it, and the inventories of libraries that burned. What survives is a negative image: the shape of an absence, traced by everything that pressed against it. The catalogue of Alexandria is the obvious example, though it has been mythologised beyond usefulness. More instructive are the smaller losses. A twelfth-century Andalusian treatise on optics survives only because a Latin translator argued with it at length before dismissing it. His hostility preserved what his agreement would have buried in a footnote. This produces an uncomfortable methodological consequence. Our picture of any lost text is shaped decisively by the temperament of whoever happened to mention it. A generous summariser leaves us a fuller work than a hostile one; a pedant who quotes at length is worth more to posterity than an admirer who merely praises. Scholarship inherits not the book but the attention it provoked. Something similar governs institutional memory more broadly. Organisations retain not what mattered most but what generated the most correspondence. Decisions taken quietly, competently, without dispute, leave almost no trace. The archive is systematically biased toward conflict, because conflict generates paper. The implication for anyone writing history is not that the record lies, but that it is shaped by a selection process nobody designed and few acknowledge. Absence is rarely neutral. Things vanish for reasons, and the reasons are frequently more interesting than the things. There is a further irony worth noting. The scholarship of lost books is itself unusually fragile. It exists in specialist journals with tiny circulations, maintained by a few dozen people, dependent on institutional funding that assumes its value is self-evident. Should that funding stop, the discipline would leave behind exactly what it studies: citations in the work of others, an inventory, and the outline of something that was once there. Its practitioners are aware of this. Several have remarked on it, in print, with the particular dryness of people who have spent their careers examining the mechanics of disappearance and have no illusions about their own.