Why must biographers test the authenticity of their sources?

Biographers must rigorously test the authenticity of their sources because the historical record is frequently compromised. Many collections of papers, letters, and memorabilia edited before the 20th century are unreliable, as editors often omitted or transposed materials to suit their own purposes. Furthermore, subjects themselves sometimes revised their personal writings for posterity, effectively falsifying the record.1

Testing evidence is a fundamental responsibility of the biographer, as it ensures the integrity of the narrative and protects against the dissemination of inaccurate information. When dealing with a living subject, this process is even more critical; the biographer must evaluate the subject's personal perspective against multiple, potentially contradictory sources to maintain historical accuracy. Ultimately, the biographer has an ethical obligation to preserve the truth, which requires a diligent and critical approach to all collected materials.12