How I Turned My Coin Collecting Expertise Into a $50,000 Online Course on Teachable
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October 1, 2025Ever stared at a rare coin and thought, “There’s got to be a better way to verify this?” That’s exactly where I started. As a data validation specialist by day and coin collector by night, I saw patterns others missed. The same rigor I applied to software systems could crack open coin authentication. This post is my real story of turning that spark into a real O’Reilly Media book — complete with late-night coding sessions, nervous proposal emails, and the surprising tech community that helped it grow.
Why Write a Technical Book?
I’ve spent years building systems that validate data, detect fraud, and automate decisions. But weekends were for coins — especially the kind that make collectors nervous: Is it real? Graded fairly? Worth the asking price?
That’s when it hit me: coin authentication isn’t just about gut feelings. It’s a technical problem.
Think about it. Authenticating a coin means:
- Measuring physical properties (weight, density, composition)
- Analyzing surface patterns (doubling, die errors, post-mint damage)
- Tracing provenance (mint records, ownership history)
- Modeling market value (trends, demand, risk)
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Sound familiar? It’s exactly like testing a distributed system or training an ML model.
And that’s why I wrote the book: Automated Coin Authentication: Tools, Techniques, and Valuation Algorithms. Not for casual collectors. For the engineers, data scientists, and product builders who see numismatics as a domain of signals, not stories.
The Value of a Technical Book in a Niche Domain
Skeptical? I was too. Writing a book felt like a luxury — until I realized it was a tool.
My book has been used by:
- Blockchain teams building provenance trackers for rare coins
- AI researchers training image models on NGC-graded datasets
- Fintech startups automating appraisal workflows
I didn’t write a “this coin is worth $10,000” guide. I wrote a manual for turning coin analysis into code. That’s what made it stick.
Structuring the Book: From Hobby to Technical Framework
Here’s the mistake most make: they write a memoir, not a manual.
I started with a question: How would I build a coin grading API? That mindset shift — from storytelling to system design — shaped the entire book.
Chapter Architecture: The 5-Tier Validation Model
Instead of listing “rare coins,” I built a five-layer technical pipeline:
- Image Acquisition — How to capture coins under consistent lighting and angles (with code for OpenCV setup)
- Material Analysis — Using weight, diameter, and thickness to estimate density (and flag plating or filler)
- Surface & Strike Analysis — Detecting doubling, die cracks, and re-engraving via pattern recognition
- Historical Context — Mining mint records, auction archives, and blockchain provenance logs
- Market Modeling — Building valuation algorithms with sentiment, scarcity, and auction history
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Each chapter followed the same rhythm:
- A real coin problem (e.g., “Is this 1966 half dollar real?”)
- A technical approach (e.g., “Let’s calculate expected density”)
- Code, diagrams, and a test case
Code Example: Weight-to-Composition Validation
The most shared chapter? The one that turned coin guessing into a function.
def validate_silver_coin(weight_g, diameter_mm, thickness_mm, expected_percentage=0.90):
"""Check if a coin matches expected silver composition by density."""
volume_cm3 = (3.14159 * (diameter_mm / 2)**2 * thickness_mm) / 1000
density_g_cm3 = weight_g / volume_cm3
# 90% silver: ~10.36 g/cm3 | 40% silver (clad): ~9.00 g/cm3
if 10.2 <= density_g_cm3 <= 10.5:
return f"Likely {expected_percentage*100}% silver (density: {density_g_cm3:.2f})"
elif 8.5 <= density_g_cm3 <= 9.2:
return "Clad or low-silver (density: {:.2f})".format(density_g_cm3)
else:
return "Anomalous density: possible damage, plating, or error"
# Test: 1966 Kennedy Half Dollar
print(validate_silver_coin(11.5, 30.6, 2.15)) # Likely 90% silver (density: 10.31)Suddenly, “feels like silver” became “objective density range.” Engineers loved it. Collectors started sharing it with their clubs.
Crafting a Winning Book Proposal
Got an idea? Great. Now prove it matters.
Publishers get hundreds of “I wrote a book about X” emails. I sent one that answered: “Why now? Who needs this? And what makes it technical?”
1. Market Analysis (The “Why Now?” Section)
I didn’t just say “coins are cool.” I showed:
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- AI image models (YOLO, COCO) being trained on coin datasets
- Blockchain platforms selling rare coins as NFTs — with need for verification
- PCGS and NGC processing millions of coins annually — but little public automation
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2. Competitive Landscape
Existing options?
- Red Book: Great for collectors, zero code
- Academic journals: Deep, but no reusable tools
- Blogs “Top 10 Rare Coins” — more gossip than science
My book filled the gap: a technical playbook for reproducible authentication.
3. Target Audience
I defined three readers:
- Software engineers building authentication tools (e.g., for auction sites)
- Data scientists training models on coin images
- Finance pros evaluating numismatic investment platforms
4. Sample Chapter
I sent Chapter 3: “Automated Edge Analysis for Clad vs. Silver Coins” with:
- Python edge detection code
- Jupyter notebooks with test cases
- Images of real anomalies (like a 1981-D dime with incorrect weight)
It wasn’t just a chapter. It was a demo.
Pitching to Publishers: O’Reilly vs. Manning vs. Apress
O’Reilly: The Tech Leader
O’Reilly doesn’t want nostalgia. They want tools. I pitched:
- Integration with Jupyter, OpenCV, TensorFlow
- APIs for third-party grading services
- Ultrasonic testing for haptic feedback (yes, that’s in the book)
Manning: The Educator
Manning likes learning paths. So I proposed:
- “Grading Labs” — hands-on projects like building a chatbot grader
- Video walkthroughs using OBS (recorded in my garage, with coin trays and calipers)
Apress: The Pragmatic
Apress wants ROI. I highlighted:
- “5 scripts to automate grading” — fast, practical wins
- Case studies from real grading disputes (e.g., the 1975 SMS quarter controversy)
I picked O’Reilly — not just for the brand, but for their audience of builders.
Building an Audience: The Pre-Launch Strategy
Here’s the surprise: the book started growing before it was finished.
1. GitHub Repository
I launched coin-authentication-tools with:
- Source code for all scripts (density, edge detection, provenance scraping)
- Public datasets from PCGS/NGC auctions
- An issue tracker for collectors to submit coins for analysis
Within a week, someone asked: “Can your script detect a doubled die on a 1955 cent?” I added it — and credited them.
2. Tech Blog & Newsletter
Instead of “coin tips,” I wrote about:
- “How I Used ML to Detect a Fake 1966 Half Dollar”
- “Why Your Coin’s Weight Might Be Lying to You”
- “The 5-Step Checklist Before Submitting to PCGS”
Readers weren’t just collectors. They were engineers asking: “Can this work for art authentication?”
3. Speaking & Webinars
I spoke at:
- PyData: “Computer Vision for Numismatics”
- Blockchain Conferences: “Provenance Tracking for Rare Coins”
- O’Reilly Events: Hosted a “Coin Grading Lab” workshop
The result? A community of 10K+ readers — many pre-ordered the book. Some even sent me coins to “test the scripts.”
Navigating the Writing Process
Tools & Environment
- O’Reilly’s AsciiDoc — for clean, format-agnostic manuscripts
- Jupyter Notebooks — to embed runnable code in chapters
- GitHub Issues — to track feedback from editors (“Clarify this on page 142”)
Writing Schedule
I used a 90-day sprint:
- Weeks 1–30: Draft chapters (one per week)
- Weeks 31–60: Code, diagrams, and case studies
- Weeks 61–75: Sent to 10 experts for peer review
- Weeks 76–90: O’Reilly review and final edits
Handling Criticism
One reviewer said: “This chapter on fire-damaged coins is too subjective.”
My response? I didn’t argue. I added:
- A quantitative damage scale (e.g., heat deformation in microns)
- Spectral analysis code to detect material changes
That chapter became one of the most cited.
Conclusion: The ROI of a Technical Book
The book didn’t just sell. It changed things.
- Speaking gigs at tech and finance conferences
- Consulting work with grading services and auction platforms
- VC interest in building a coin authentication SaaS
- Named to O’Reilly’s “Top 10 Tech Books of 2023”
Here’s what I learned:
- Structure like an engineer — your book is a system, not a journal
- Publishers want evidence — show demand, not just passion
- Build the audience early — GitHub, blogs, and talks matter more than you think
- Code is credibility — readers trust a script more than a statement
Whether you’re writing about coin authentication, machine learning, or cloud security — treat it like a technical problem, not a memoir. That’s how you turn a passion into a book that matters.
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