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What's It Worth? A History of Guessing

Seven valuation sources, trend tracking over time, provenance auto-sync, and the art of estimating value without a crystal ball.

3 min

The value of a rare book is a guess dressed up as a number. It changes with the market, the condition, the provenance, and the mood of the person being asked. Shelvd tracks these guesses over time.

Valuation Sources

Each valuation entry in Shelvd specifies a source — where the estimate came from:

  • Self-estimate — your own assessment based on experience, comparables, or intuition
  • Appraisal — a formal valuation by a certified appraiser
  • Auction result — an actual hammer price (the most honest number)
  • Dealer quote — what a dealer offered or asked
  • Insurance — the insured value (often higher than market)
  • Market research — based on checking prices on AbeBooks, Rare Book Hub, viaLibri, etc.
  • Provenance purchase — the price you actually paid (auto-created from provenance entries with a price)

Adding Valuations

On the Edit page, scroll to the Valuation History section. Each entry includes:

  • Date — when the valuation was made
  • Amount — the estimated value
  • Currency — which currency the value is expressed in
  • Source — one of the seven types above
  • Notes — context: "Based on Sotheby's sale of comparable copy, lot 156, Nov 2024"

Trend Tracking

When a book has two or more dated valuations, Shelvd displays a value trend chart on the detail page. This shows how the book's estimated value has changed over time — useful for tracking appreciation, market shifts, or the effect of restoration.

Provenance Auto-Sync

When you add a provenance entry with a price paid, Shelvd automatically creates a corresponding valuation history entry with source "provenance_purchase." This means your acquisition price is always part of the valuation timeline.

Gain/Loss

The book detail page shows a gain/loss calculation: what you paid (acquired cost) versus the most recent valuation. "Bought €500 → Estimated €750 (+50%)" appears in green. "Bought €500 → Estimated €300 (−40%)" appears in red. Both are truths you should know.

The Stats Connection

The Statistics dashboard aggregates valuation data across your library: total acquired cost, total estimated value, unrealized gain/loss. All amounts are converted to your display currency using daily ECB exchange rates.

A Note on Honesty

Valuation is not an exact science. A book is worth what someone will pay for it, and nobody knows what that is until the moment of sale. Record your best estimates, update them when new information arrives, and resist the temptation to round up. Your catalog is a tool for truth, not a comfort blanket.

📖 Related on the blog: Cataloging for Insurance, The Auction Room