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3,887 Ways to Categorize a Book (And Still Get It Wrong)

BISAC subject headings — primary, secondary, tertiary — and the quiet futility of putting books in exactly one box.

3 min

BISAC stands for Book Industry Standards and Communications — a system of subject codes used by publishers, booksellers, and libraries to categorize books. Shelvd contains the complete 2025 BISAC Subject Headings List: 3,887 codes across dozens of major categories.

How BISAC Works

Each code consists of a three-letter prefix (the major category) followed by a six-digit number:

  • FIC000000 — Fiction / General
  • FIC014000 — Fiction / Historical
  • HIS015000 — History / Europe / Western
  • ART016000 — Art / History / General

The system is hierarchical: major category → subcategory → specific topic. It's designed to answer the question "where does this book go in a bookstore?" — which is a useful question, even if the answer is sometimes "in three places at once."

Three BISAC Fields

Shelvd offers three BISAC fields:

  • Primary BISAC — the main category. Required for professional cataloging.
  • Secondary BISAC — an optional cross-listing for books that span categories.
  • Tertiary BISAC — a third category for the truly uncategorizable.

A book on the history of Japanese woodblock printing might be: Art / Asian (primary), History / Asia / Japan (secondary), Crafts & Hobbies / Printmaking (tertiary).

Choosing the Right Code

The BISAC dropdown in Shelvd is searchable — type "medieval" and you'll see all codes containing that word. Some tips:

  • Be specific when you can. "Fiction / Historical / Medieval" is better than "Fiction / General."
  • Use the primary code for the strongest subject match.
  • Don't overthink it. BISAC is a shelving tool, not a philosophical framework. A "close enough" code is better than no code at all.
  • Fiction vs. Nonfiction is the first decision. Everything follows from there.

When to Care

If you're a collector cataloging for personal use, BISAC is optional. Your tags and collections might serve you better.

If you're a dealer preparing records for sale, BISAC codes help buyers find your books in online marketplaces and databases.

If you're a librarian, you already know more about BISAC than this article can teach you, and we apologize for wasting your time.

The Futility

No classification system perfectly captures what a book is about. A biography of a scientist who wrote poetry — is that Biography, Science, or Poetry? A cookbook from the eighteenth century — is that Cooking, History, or Antiques & Collectibles?

BISAC gives you 3,887 options. It's still not enough. That's not a flaw in the system — it's a feature of books.