The Collation

Research and Exploration at the Folger

Physical description in book cataloging

Does a4 A-O8 P10 make perfect sense to you? If so, please read on anyway. This isn’t a post on how to decode a collational formula. It’s a post about what to expect (and what not to expect) in the “physical description” portion of a library catalog record for a book.1 In other words, the part that looks like this in a Hamnet record, taking the record for the 1513 Venetian edition of Macrobius’s Commentaries on the Dream of Scipio as an example:2

Brief summary of page numbers, illustration, and size
Example of a “physical description” in a Hamnet record.

International Standard Bibliographic Description (yes, there is an international standard) calls this part of the record the Material Description Area.3 In Anglo-American library cataloging, it’s called the Physical Description Area.4 At the Folger, as at the Library of Congress, our catalogs label it simply “Description.” It has three basic parts (“subfields” in library-speak) separated by a punctuation mark with a space on ether side.

The first part of the physical description, [4], CXXII leaves in this example, is the “statement of extent.” The statement of extent must account for every leaf of the book as issued by the publisher (if one or more of a particular library’s copies are missing leaves, that gets noted in the portion of the record devoted to copy-specific information). The statement of extent is sometimes referred to as the “pagination statement” because it doesn’t give the number of pages as such, it gives the numbering of the pages in a way that allows the extent to be calculated. Or, as in this case, it presents the information in terms of leaves rather than pages (called “foliation,” in contrast to “pagination”) because that’s how the book presents itself: sequential Roman numerals on the recto of each leaf, and no numbering on the verso, as you can see in this photo of the final opening.

Note the leaf number in the upper right corner of the right hand page, and the lack of number in the upper left corner of the left hand page.

We know from the catalog record that there are four unnumbered leaves before the numbering begins because the statement of extent starts [4]—the square brackets indicate information that has not been transcribed from the source, but is known to be accurate. We also know there are 122 numbered leaves, and that they are numbered in Roman numerals, because the pagination statement ends CXXII (the roman numeral for 122, printed at the upper right of the last leaf, shown in the picture). Note that the statement only gives the final number of the sequence, not the actual numbers appearing on each leaf: unless otherwise stated, it’s assumed that counting back from the end of the sequence will get you to “one”.

Leaf LXI was misprinted, but a helpful annotator provided the correct number.

But what happens in the statement of extent if the numbering in the book is wrong? Answer: nothing, unless it affects the final numbers. Because the statement is only a statement of extent, mis-numbering that does not change the totals is out-of-scope. In our Macrobius example, the leaf that should have been numbered LXI wasn’t (and happens to have been corrected by an early owner) but  no mention is made in the statement of extent because there are still 122 leaves in the sequence, and the last number is printed correctly as CXXII.5 This isn’t to say that there aren’t plenty of books where mis-numbering doesn’t self correct, or doesn’t self-correct within a reasonable number of pages, but that’s a story for another day.

The second part of the physical description of a book (ill. in our example) is known as the “illustration statement.” This is where the cataloger indicates whether the book contains illustrations, and sometimes provides additional information about those illustrations. If the book does have illustrations, their presence is indicated by the abbreviation ill., as was done in this record. If a book is unillustrated, the physical description jumps straight from the statement of extent to the statement of size and format.

The statement of size and format typically forms the last part of the physical description of an early modern book, as with the 31 cm (fol.) in our Macrobius example. The first portion indicates size by giving the height of the book (including binding, if present) rounded up to the nearest whole centimeter.6 Library catalogs only give the width of the book if it’s unusually wide or unusually skinny. The abbreviation in parentheses indicates the bibliographic format of the book: folio, in this case, meaning that the book is made up of sheets of paper folded in half once.

These three statements—of extent, of illustration, and of size and format—form a complete physical description in a library catalog.

What about the a4 A-O8 P10 part mentioned at the start of this post? Shouldn’t the collation be part of the physical description of a book? Check back Thursday for a follow-up post. [Update: follow-up now posted]


  1. Huge thanks go out to Deborah J. Leslie, Senior Cataloger at the Folger and Rare Book Cataloging instructor at Rare Book School, for her corrections and improvements to the draft version of this post.
  2. See the entire record used in this example.
  3. ISBD : International Standard Bibliographic Description. Consolidated edition. Berlin and Boston: De Gruyter Saur, 2011, pp. 157-184.
  4. Descriptive Cataloging of Rare Materials (Books). Washington, DC: Cataloging Distribution Service, Library of Congress, 2007, pp. 101-118.
  5. The mis-numbering in the Macrobius example could be described in the “notes” section of the catalog record, if considered important. It just doesn’t go in the statement of extent.
  6. Books less than 10 cm high, however, get measured instead in millimeters.


  • A note on the statement of size:

    The height of the binding is meaningful for books in publishers’ bindings (post-1830) and possibly helps librarians to shelve the books economically. It is not nearly so useful for earlier books which were individually bound and where any copy of an edition is likely to have a different size of binding from every other copy.

    Much more useful for early printed books is a record of the physical page dimensions of each copy (which will be a little smaller than the size of the binding). From the page size (height and width) and the format, it is possible to calculate an estimate of the size of the sheets on which the book was printed and to identify which of the conventional sheet size was being used. This is being increasingly done in catalogues of incunables (15th-century printed books). I expect that cataloguers of modern books will think that this requirement would be the tail wagging the dog.

    • Excellent point. Rare books cataloging rules do take variations in binding height into account to some degree: “If more than one copy of the publication is held, and the heights of the different copies vary, record the height of the tallest copy and give the height of the other copies in a local note” and “when the height of the publication differs by 3 centimeters or more from the hight of the binding, specify both.”—DCRM(B) 5D1.1 and 5D1.2, respectively.
      Because binders trim the text block as part of the binding process, though, I don’t know that measuring the page would that much more informative: the size of the page tends to vary roughly in relation to the height and width of the binding (and for copies that have been bound and rebound several times, can sometimes mean the outer margins are almost completely gone).
      For the same reason, I’d love it if catalog records always mentioned whether a particular copy had any untrimmed leaves. If you have a folio where the deckle edges are still intact, you know exactly how big the original sheet of paper was. (And I’ve just remembered that there’s a great example of this in the Folger collection! I’ll head down to the vault with a ruler in a moment. It’s the recently-discovered only known complete copy of STC 22527a.5—before it resurfaced, that edition was only known through an engraved title page in the Department of Prints and Drawings at the British Museum, and from that page’s size it was assumed to be an octavo. In fact, it turns out to be an unusually small folio.)

  • A quick search of Hamnet reveals that some 1250 records include the words “untrimmed” in the Folger copy notes, and an additional 500 include “uncut.”

    I suspect that many copies in the latter group are in fact “unopened.” In bibliographical circles, “uncut” is a shibboleth: the initiated know that uncut means untrimmed, and that unopened means that the bolts connecting the top of gatherings are still intact. Many educated and intelligent people who happen not to be initiated into the mysteries of descriptive bibliography innocently describe unopened books as “uncut.” For that reason, I avoid the use of “uncut” in descriptions and urge others to do the same, using “untrimmed” or “unopened” (or both) as appropriate.

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