The best-selling, easiest, step-by-step, most comprehensive guide to securing your home or business OS X computers. Completely revised and updated for OS X 10.11, El Capitan.Official workbook for the Practical Paranoia: Security Essentials Workshop. Designed for both workshop use and self-study. The entire workshop is contained within the book. Includes all instructor presentations, hands-on assignments, links to all software, and security checklist.