What makes a book valuable

First edition first printing is the foundation. The first edition is the first time the work was published. The first printing is the first run of that edition. Subsequent printings of the same edition are worth less, sometimes significantly less

Learning to identify first editions requires understanding the specific points, the bibliographic details that distinguish first printings from later ones, for each author and publisher you collect. Condition and dust jacket is the second major variable. The dust jacket of a twentieth-century first edition can represent the majority of the total value. A first edition of The Great Gatsby without its original dust jacket is worth a fraction of the same book with a fine copy of the jacket

Signatures and inscriptions add value in proportion to the significance of the signer and the relationship documented by the inscription. Association copies, books that belonged to notable individuals and document that relationship through bookplates, inscriptions, or annotations, can be worth many times the value of the same book without the association.

CollectorGrade take

The dust jacket of a twentieth-century first edition is often the majority of the value. A collector who does not understand dust jacket condition and scarcity is operating with a significant blind spot.