The first property of the Primer is that it is either book-like—that is, it looks like a classic analog book—or "embooked," meaning it is physically embedded into a classic analog book. This first characteristic implies that the Primer:

uses reflected, non-emitted light (i.e., E-Ink rather than LED or OLED) to display content

ideally consists of multiple pages that can be read on both sides and are bound together using special binding techniques,

is equipped with both internal and external content encoding on the front and back covers and can include an additional layer of protection (e.g., a protective cover),

has a standardized format (e.g., A5) that allows it to be easily carried in existing wearables (e.g., school bags) and stored or archived in existing furniture (e.g., bookshelves)