Fortinet Technical Documentation for FortiOS 5.2
 
The FortiOS 5.2 Handbook - The Complete Guide FortiGate Cookbook 5.2

 FortiGate Authentication  FortiGate VM Install
 FortiOS 5.2 Best Practices  Compliance
 FortiGate Firewall  FortiGate Hardware Acceleration
 FortiGate Install System Admin  FortiGate IPSec
 FortiGate Troubleshooting  FortiGate Load Balance
 FortiGate Logging & Reporting  FortiGate Max-Values
 FortiGate SSL VPN  FortiGate Traffic Shaping
 FortiGate Security Profile  FortiGate vDoms
 FortiGate VOIP-SIP  FortiGate Wan Opt Cache Proxy
 FortiOS 5.2 Whats New  FortiGate Wireless
 FortiGate Advanced Routing  Inside FortiOS Authentication
 Open Ports Diagrams  FortiView

Fortinet Technical Documentation for FortiOS 5
 
The FortiOS 5 Handbook - The Complete Guide FortiGate Cookbook 5.0

 FortiGate Authentication  FortiGate VM Install
 FortiGate Firewall  FortiGate Hardware Acceleration
 FortiGate Install System Admin  FortiGate IPSec
 FortiGate Troubleshooting  FortiGate Load Balance
 FortiGate Logging & Reporting  FortiGate Max-Values
 FortiGate SSL VPN  FortiGate Traffic Shaping
 FortiGate Security Profile  FortiGate vDoms
 FortiGate VOIP-SIP  FortiGate Wan Opt Cache Proxy
 FortiGate Whats New  FortiGate Wireless
 FortiGate Advanced Routing  Inside FortiOS Authentication
Connecting an Android to a FortiGate with SSL VPN

Fortinet Technical Documentation for FortiOS 4 MR 3
 
The FortiOS 4 Handbook - The Complete Guide FortiGate Cookbook 4.3

 FortiGate Authentication  FortiGate Troubleshooting
 FortiGate Firewall  FortiGate HA
 FortiGate System Admin  FortiGate IPSec
 FortiGate LMR  FortiGate Load Balance
 FortiGate Logging Optimization  FortiGate Max-Values
 FortiGate SSL VPN  FortiGate Traffic Shaping
 FortiGate UTM  FortiGate vDoms
 FortiGate VOIP-SIP  FortiGate Wan Opt Cache Proxy
 FortiGate Whats New  FortiGate Wireless
 FortiGate Advanced Routing  FortiGate CLI
 FortiGate Compliance  FortiGate FortiCarrier
 FortiGate Hardware  FortiGate Logging & Reporting