Marginalia are a variety of writings and symbols written by readers in book margins. This study focuses on marginalia and explores the reading practices and the scholarly culture of late Imperial China. Beginning in the late Ming and early Qing, more scholars devoted themselves to reading and collating ancient texts. They developed the habit of writing marginalia while reading, of transcribing other readers’ marginalia, and of printing marginalia, all of which formed a particular scholarly culture. This book explores how this culture developed, gained momentum, and shaped the styles, lives, thoughts, and mind states of scholars in late Imperial China.