a. The copyright law (title 17, United States Code) requires that copies or phonorecords deposited in the Copyright Office be of the “best edition” of the work. The law states that “The ‘best edition’ of a work is the edition, published in the United States at any time before the date of deposit, that the Library of Congress determines to be most suitable for its purposes.” (For works first published only in a country other than the United States, the law requires the deposit of the work as first published.)

b. When two or more editions of the same version of a work have been published, the one of the highest quality is generally considered to be the best edition. In judging quality, the Library of Congress will adhere to the criteria set forth below in all but exceptional circumstances.

c. Where differences between editions represent variations in copyrightable content, each edition is a separate version and “best edition” standards based on such differences do not apply. Each such version is a separate work for the purpose of the copyright law.

d. The criteria to be applied in determining the best edition of each of several types of material are listed below in descending order of importance. In deciding between two editions, a criterion-by-criterion comparison should be made. The edition which first fails to satisfy a criterion is to be considered of inferior quality and will not be an acceptable deposit. Example: If a comparison is made between two hardbound editions of a book, one a trade edition printed on acid-free paper, and the other a specially bound edition printed on average paper, the former will be the best edition because the type of paper is a more important criterion than the binding.

e. Under regulations of the Copyright Office, potential depositors may request authorization to deposit copies or phonorecords of other than the best edition of a specific work (e.g., a microform rather than a printed edition of a serial), by requesting “special relief” from the deposit requirements. All requests for special relief should be in writing and should state the reason(s) why the applicant cannot send the required deposit and what the applicant wishes to submit instead of the required deposit.

I. Printed Textual Matter

A. Paper, Binding, and Packaging:

1. Archival-quality rather than less-permanent paper.

2. Hard cover rather than soft cover.

3. Library binding rather than commercial binding.

4. Trade edition rather than book club edition.

5. Sewn rather than glue-only binding.

6. Sewn or glued rather than stapled or spiral-bound.

7. Stapled rather than spiral-bound or plastic-bound.

8. Bound rather than looseleaf, except when future looseleaf insertions are to be issued. In the case of looseleaf materials, this includes the submission of all binders and indexes when they are part of the unit as published and offered for sale or distribution. Additionally, the regular and timely receipt of all appropriate looseleaf updates, supplements, and releases including supplemental binders issued to handle these expanded versions, is part of the requirement to properly maintain these publications.

9. Slip-cased rather than nonslip-cased.

10. With protective folders rather than without (for broadsides).

11. Rolled rather than folded (for broadsides).

12. With protective coatings rather than without (except broadsides, which should not be coated).

B. Rarity:

1. Special limited edition having the greatest number of special features.

2. Other limited edition rather than trade edition.

3. Special binding rather than trade binding.

C. Illustrations:

1. Illustrated rather than unillustrated.

2. Illustrations in color rather than black and white.

D. Special Features:

1. With thumb notches or index tabs rather than without.

2. With aids to use such as overlays and magnifiers rather than without.

E. Size:

1. Larger rather than smaller sizes. (Except that large-type editions for the partially-sighted are not required in place of editions employing type of more conventional size.)

II. Photographs

A. Size and finish, in descending order of preference:

1. The most widely distributed edition.

2. 8 × 10-inch glossy print.

3. Other size or finish.

B. Unmounted rather than mounted.

C. Archival-quality rather than less-permanent paper stock or printing process.

III. Motion Pictures

Film medium is considered a better quality than any other medium. The formats under “film” and “video formats” are listed in descending order of preference:

A. Film:

1. Preprint material, by special arrangement.

2. 70 mm positive print, if original production negative is greater than 35 mm.

3. 35 mm positive prints.

4. 16 mm positive prints.

B. Video Formats:

1. Betacam SP.

2. Digital Beta (Digibeta).

3. DVD.

4. VHS Cassette.

IV. Other Graphic Matter

A. Paper and Printing:

1. Archival quality rather than less-permanent paper.

2. Color rather than black and white.

B. Size and Content:

1. Larger rather than smaller size.

2. In the case of cartographic works, editions with the greatest amount of information rather than those with less detail.

C. Rarity:

1. The most widely distributed edition rather than one of limited distribution.

2. In the case of a work published only in a limited, numbered edition, one copy outside the numbered series but otherwise identical.

3. A photographic reproduction of the original, by special arrangement only.

D. Text and Other Materials:

1. Works with annotations, accompanying tabular or textual matter, or other interpretative aids rather than those without them.

E. Binding and Packaging:

1. Bound rather than unbound.

2. If editions have different binding, apply the criteria in I.A.2-I.A.7, above.

3. Rolled rather than folded.

4. With protective coatings rather than without.

V. Phonorecords

A. Compact digital disc rather than a vinyl disc.

B. Vinyl disc rather than tape.

C. With special enclosures rather than without.

D. Open-reel rather than cartridge.

E. Cartridge rather than cassette.

F. Quadraphonic rather than stereophonic.

G. True stereophonic rather than monaural.

H. Monaural rather than electronically rechanneled stereo.

VI. Musical Compositions

A. Fullness of Score:

1. Vocal music:

a. With orchestral accompaniment:

i. Full score and parts, if any, rather than conductor's score and parts, if any. (In cases of compositions published only by rental, lease, or lending, this requirement is reduced to full score only.)

ii. Conductor's score and parts, if any, rather than condensed score and parts, if any. (In cases of compositions published only by rental, lease, or lending, this requirement is reduced to conductor's score only.)

b. Unaccompanied: Open score (each part on separate staff) rather than closed score (all parts condensed to two staves).

2. Instrumental music:

a. Full score and parts, if any, rather than conductor's score and parts, if any. (In cases of compositions published only by rental, lease, or lending, this requirement is reduced to full score only.)

b. Conductor's score and parts, if any, rather than condensed score and parts, if any. (In cases of compositions published only by rental, lease, or lending, this requirement is reduced to conductor's score only.)

B. Printing and Paper:

1. Archival-quality rather than less-permanent paper.

C. Binding and Packaging:

1. Special limited editions rather than trade editions.

2. Bound rather than unbound.

3. If editions have different binding, apply the criteria in I.A.2-I.A.12, above.

4. With protective folders rather than without.

VII. Microforms

A. Related Materials:

1. With indexes, study guides, or other printed matter rather than without.

B. Permanence and Appearance:

1. Silver halide rather than any other emulsion.

2. Positive rather than negative.

3. Color rather than black and white.

C. Format (newspapers and newspaper-formatted serials):

1. Reel microfilm rather than any other microform.

D. Format (all other materials):

1. Microfiche rather than reel microfilm.

2. Reel microfilm rather than microform cassetes.

3. Microfilm cassettes rather than micro-opaque prints.

E. Size:

1. 35 mm rather than 16 mm.

VIII. Machine-Readable Copies

A. Computer Programs:

1. With documents and other accompanying material rather than without.

2. Not copy-protected rather than copy-protected (if copy-protected then with a backup copy of the disk(s)).

3. Format:

a. PC-DOS or MS-DOS (or other IBM compatible formats, such as XENIX):

(i) 51⁄4 ″ Diskette(s).

(ii) 31⁄2 ″ Diskette(s).

(iii) Optical media, such as CD-ROM—best edition should adhere to prevailing NISO standards.

b. Apple Macintosh:

(i) 31⁄2 ″ Diskette(s).

(ii) Optical media, such as CD-ROM—best edition should adhere to prevailing NISO standards.

B. Computerized Information Works, Including Statistical Compendia, Serials, or Reference Works:

1. With documentation and other accompanying material rather than without.

2. With best edition of accompanying program rather than without.

3. Not copy-protected rather than copy-protected (if copy-protected then with a backup copy of the disk(s)).

4. Format:

a. PC-DOS or MS-DOS (or other IBM compatible formats, such as XENIX):

(i) Optical media, such as CD-ROM—best edition should adhere to prevailing NISO standards.

(ii) 51⁄4 ″ Diskette(s).

(iii) 31⁄2 ″ Diskette(s).

b. Apple Macintosh:

(i) Optical media, such as CD-ROM—best edition should adhere to prevailing NISO standards.

(ii) 31⁄2 ″ Diskette(s).

IX. Electronic Works Published in the United States and Available Only Online

For all deposits, UTF-8 encoding is preferred to ASCII encoding and other non UTF-8 encodings for non-Latin character sets in all categories below.

A. Electronic Serials:

1. Content Format:

a. Level 1: Serials-specific structured/markup format:

(i) Content compliant with the NLM Journal Archiving (XML) Document Type Definition (DTD), with presentation stylesheet(s), rather than without.

(ii) Other widely used serials or journal XML DTDs/schemas, with presentation stylesheet(s), rather than without.

(iii) Proprietary XML format for serials or journals (with documentation), with DTD/schema and presentation stylesheet(s), rather than without.

b. Level 2: Page-oriented rendition:

(i) PDF/A (Portable Document Format/Archival; compliant with ISO 19005).

(ii) PDF (Portable Document Format, with searchable text, rather than without).

c. Level 3: Other formats:

(i) XHTML/HTML, as made available online, with presentation stylesheets(s), rather than without.

(ii) XML (widely used, publicly documented XML-based word-processing formats, e.g., ODF/OpenDocument Format, Office OpenXML), with presentation stylesheets(s), if appropriate, rather than without.

(iii) Plain text.

(iv) Other formats (e.g., proprietary word processing or page layout formats).

2. Metadata Elements:

If it has already been gathered and is available, descriptive data (metadata) as described below should accompany the deposited material.

a. Title level metadata: serial or journal title, ISSN, publisher, frequency, place of publication.

b. Article level metadata, as relevant/applicable: volume(s), number(s), issue dates(s), article title(s), article author(s), article identifier (DOI, etc.).

c. With other descriptive metadata (e.g., subject heading(s), descriptor(s), abstract(s)), rather than without.

3. Technological measures that control access to or use of the work should be removed.

X. Works Existing in More Than One Medium

Editions are listed below in descending order of preference.

A. Newspapers, dissertations and theses, newspaper-formatted serials:

1. Microform.

2. Printed matter.

B. All other materials:

1. Printed matter.

2. Microform.

3. Phonorecord.

[54 FR 42299, Oct. 16, 1989, as amended at 62 FR 51603, Oct. 2, 1997; 69 FR 8822, Feb. 26, 2004; 75 FR 3869, Jan. 25, 2010; 82 FR 9362, Feb. 6, 2017; 83 FR 61550, Nov. 30, 2018]