Modern Master Key
Original Text + Focus Training
Free · In‑App Purchases
Read the original public-domain text free. Premium adds optional guided study and focus tools.
Modern Master Key provides mobile access to Charles F. Haanel's The Master Key System.
The complete core text is available free in the app. Premium is optional and adds structured study tools for readers who want more guidance.
### About
This app reproduces the public-domain text of The Master Key System, originally published beginning in 1912 and compiled in early 20th-century editions.
The text is based on historical source material and presented as faithful reading text.
Public-domain text in app:
- Lesson text (24 parts)
- Introduction
- Glossary
App-created features:
- Reading UI and navigation
- Universal search, progress, and reminder controls
- Highlights, bookmarks, and notes
- Focus session timers, streaks, badges, and reflection tools
- Spaced review and export utilities
- Live Activity support for active focus sessions
- Apple Watch companion support
### Free Features
- Complete 24-part core text
- Introduction and glossary
- Universal search
- Reading progress and weekly reminder controls
### Optional Premium Features
- Guided 24-week focus workflow
- Discipline Mode (structured progression)
- Timed focus sessions and reflection tracking
- Streaks, badges, and advanced focus progress metrics
- Study tools: bookmarks, highlights, notes, and Favorites Hub
- Spaced repetition review and export tools
- Key Takeaways
No medical, scientific, or guaranteed-outcome claims are made.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://modernmasterkey.com/privacy.html
Ratings & Reviews
This app hasn’t received enough ratings or reviews to display an overview.
The developer, Hartshorne Works, LLC., indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Hartshorne Works LLC
- Size
- 6.4 MB
- Category
- Books
- Compatibility
Requires iOS 17.6 or later.
- iPhone
Requires iOS 17.6 or later. - iPad
Requires iPadOS 17.6 or later. - Apple Watch
Requires watchOS 26.2 or later.
- Languages
- English
- Age Rating
9+
- 9+
- Contains
Health or Wellness Topics
- In-App Purchases
Yes
- Modern Master Key Premium Monthly $3.99
- Modern Master Key Premium Yearly $39.99
- Copyright
- © 2026 Hartshorne Works LLC
