A short book that covers the most frequently used OpenSSL
features and commands, by Ivan Ristić

Provides OpenSSL documentation that covers installation, configuration, and key and certificate management
Includes SSL/TLS Deployment Best Practices, a design and deployment guide
Written by the author of SSL Labs and the SSL/TLS configuration assessment tool
Available in a variety of digital formats (PDF, EPUB, Mobi/Kindle); no DRM

OpenSSL Cookbook is a free ebook built around two OpenSSL chapters from Bulletproof SSL and TLS, a larger work that teaches how to deploy secure servers and web applications.