These notes are intended to clarify and supplement the autobiographical writings and dictations in this volume by identifying people, places, and incidents, and by explaining topical references and literary allusions. In addition, they attempt to point out which of Clemens’s statements are contradicted by historical evidence, providing a way to understand more fully how his memories of long-past events and experiences were affected by his imagination and the passage of time. Although some of the notes contain cross-references to texts or notes elsewhere in the volume, the Index is an indispensable tool for finding information about a previously identified person or event.

All references in the notes are keyed to the text by page and line: for example, 1.1 means page 1, line 1 of the printed text. All of Clemens’s text is included in the line count (except for the main titles of pieces); excluded are the editorial headnotes in the first section, “Preliminary Manuscripts and Dictations.” Most of the source works are cited by an author’s name and a date, a short title, or an abbreviation. Works by members of the Clemens family may be found under the writer’s initials: SLC, OLC (Olivia), OSC (Susy), JC (Jean), and CC (Clara). All abbreviations, authors, and short titles used in citations are fully defined in References. Most citations include a page number (“L1, 263,” or “Angel 1881, 345”), but citations to works available in numerous editions may instead supply a chapter number or its equivalent, such as a book or act number. All quotations from holograph documents are transcribed verbatim from the originals (or photocopies thereof), even when a published form—a more readily available source—is also cited for the reader’s convenience. The location of every unique document or manuscript is identified by the standard Library of Congress abbreviation, or the last name of the owner, all of which are defined in References.