The term manuscript (from manuscriptum, Medieval Latin) describes a document which is written by hand as well as the text submitted for publication. Manuscripts can be in various forms: scroll, codex, and book. Illuminated manuscripts refers to manuscripts containing illuminations.
Manuscripts can be located in multiple ways:
Citations of manuscripts = the repository + the shelfmark of the manuscript
The Abbreviationes page provides the abbreviation for O: "codex Oxoniensis Collegii Balliol. 296." The General Introduction describes three manuscripts in detail: A, O, and R. In the description for O is "Oxford, Balliol College, ms. 296." O refers to manuscript 296 which is held by Balliol College at Oxford, England.
The Sigla page shows "C = cod. Parisinus 2080." Parisinus looks like Paris so the manuscript is probably in the National Library at Paris. To make sure, you look at the list of manuscripts listed in Xenophon in Seven Volumes I Hellenica Books I-IV in the The Loeb Classical Library (PA 3612 .X4 A2 1967 v.1, Greek and Latin Seminar Room). Next to C. you see "Parisinus 2080, in the National Library at Paris."
If you are looking for manuscripts relating to a specific topic, you will want to think of repositories who would be associated with that topic. For the topic United States History, you will want to look at catalogs of repositories in the United States such as the Library of Congress and National Archives and Records Administration. You would also want to keep in mind United States History collections in other countries such as Russia. The National Library of Russia contains the collection of Western manuscripts includes documents relating to American history; these documents contain the autographs of Benjamin Franklin, George Washington, John Adams, Thomas Jefferson, James Madison, James Monroe, and John Quincy Adams.
If you are looking for manuscripts by a specific individual such as Louisa May Alcott, you will want to consult the university or college he or she attended to see if the institution has a collection of that individual. You will also want to consult other institutions associated with a particular individual to see if the institution has manuscripts of that individual in its library, museum, or archive. You would want to find catalogs which list manuscripts for that individual. A good resource to consult for American manuscripts is the American Literary Manuscripts; A Checklist of Holdings in Academic, Historical and Public Libraries in the United States (Z6620.U5 M68 A5, Greek and Latin Seminar Room); this book lists 32 libraries whose collections include manuscripts of Louisa May Alcott.
Paul Oskar Kristeller, Latin Manuscript Books Before 1600: A List of the Printed Catalogues and Unpublished Inventories of Extant Collections. (DD3 .M831 no.13, Religious Studies and Philosophy Library Folios)
Paul Oskar Kristeller, Iter Italicum; A Finding List of Uncataloged or Incompletely Catalogued Humanistic Manuscripts of the Renaissance in Italian and Other Libraries. (Z6611.H8 K92 I8, Greek and Latin Seminar Room)
Introduction by Samantha Saporito
This LibGuide lists books, databases, and web resources which indicate where certain manuscripts can be found. The web resources also contain digitized manuscripts (complete or a selection of images) as well as aggregators of manuscript collections such as The European Library.
The Region page lists resources (websites and books) organized by country. Each country's section is organized with web resources listed at the top and books listed below the web resources.
The Greek and Latin pages list resources (databases, books, and web resources) concerning Greek and Latin manuscripts. The web resources are organized by libraries and other resources.
The U.S. Collections page lists resources (databases, books, and web resources) concerning manuscript collections in the United States and Canada. The books and web resources are organized into two divisions: Other U.S. Libraries and Manuscript Collections at Select Universities and Public Libraries.
The Images page lists subscription and free databases which provide images of manuscripts can be used for educational purposes. The databases allow images to be printed or incorporated in presentations.
The description for a book usually contains the date range of manuscripts and the languages of the manuscripts listed in the catalog. When the catalog is not in English, the decription includes the language of the catalog. The description can include examples of the types of manuscripts covered in the catalog and the subject areas covered by the manuscripts.
The description for national, academic, and public libraries includes information about the manuscripts held by that library (date range, languages, subject areas, etc.) and links to catalogs and digitized manuscripts (complete or in part).