Terms of Service

Last Updated: March 10, 2026

1. Acceptance of Terms

By downloading, installing, or using the Modern Master Key mobile application (currently available on Android via Google Play and on iOS via the Apple App Store) ("App"), you agree to these Terms of Service ("Terms"). If you do not agree, do not use the App.

2. Description of the App

Modern Master Key provides access to Charles F. Haanel's "The Master Key System," including reading tools and app features such as progress tracking and reminders.

3. Free and Premium Features

Core course access is provided at no charge. Optional premium features are available and clearly labeled before purchase.

4. Intellectual Property

Public Domain Text: "The Master Key System" (1912) is in the public domain in the United States.

App Content and Software: App design, code, branding, and original materials are owned by Hartshorne Works LLC and protected by law.

Trademarks: "Modern Master Key" and related marks/logos are property of Hartshorne Works LLC.

5. License and Permitted Use

We grant you a limited, non-exclusive, non-transferable, revocable license to use the App for personal, non-commercial use.

6. Prohibited Use

Reverse engineer, decompile, or disassemble the App except where law permits
Repackage, redistribute, or resell the App
Use the App for unlawful activity
Interfere with App operation or security

7. Privacy

Your use of the App is also governed by our Privacy Policy: https://modernmasterkey.com/privacy.html.

8. Disclaimers

The App and content are provided "AS IS" and "AS AVAILABLE," without warranties of any kind. The App provides educational and self-development content only and does not provide medical, legal, financial, or mental health advice.

9. Limitation of Liability

To the maximum extent permitted by law, Hartshorne Works LLC will not be liable for indirect, incidental, special, consequential, or punitive damages, or loss of data/profits arising from use of the App.

10. Platform Listings

The Android app is published on Google Play at https://play.google.com/store/apps/details?id=com.hartshoreworks.modernmasterkey.

The iOS app is published on the Apple App Store at https://apps.apple.com/app/modern-master-key/id6759938313.

11. Platform Terms (Apple and Google)

If downloaded from Apple App Store, use is also subject to Apple's applicable terms and policies.

If downloaded from Google Play, use is also subject to Google Play terms and policies.

Apple and Google are not responsible for the App and are not parties to these Terms except as required by their platform terms.

12. Changes to App or Terms

We may modify, suspend, or discontinue features, and may update these Terms. Continued use after updates means you accept the revised Terms.

13. Termination

You may stop using the App at any time by uninstalling it. We may suspend or terminate access for violations of these Terms.

14. Governing Law

These Terms are governed by the laws of the State of New Jersey, without regard to conflict-of-law rules.

15. Contact

Email: support@modernmasterkey.com

Website: https://modernmasterkey.com

Business Entity: Hartshorne Works LLC