Firebird documentation
Firebird 3 Quick Start Guide
Firebird 3.0 Developer's Guide (Release 1.1)
Firebird 4.0 Release Notes (12 May 2020 - Document v.0400-33 - for Firebird 4.0 Beta 2 Release)
Firebird 3.0.5 Release Notes (4 January 2020 - Document v.0305-03 - for Firebird 3.0.5 Release)
Firebird Database Cache Buffer
Firebird 2 Administration Handbook
Firebird 2 Cheat Sheet
Firebird 2.0 and 2.1 Quick Start Guide
Firebird 2 Migration & Installation
Firebird 2.0.4 Release Notes
Firebird 2.1 Error Codes
Firebird 2.1.6 Release Notes
Firebird 2.5 Quick Start Guide
Firebird 2.5.3 Release Notes
Firebird Internals
Firebird Superserver Manager
Get to know Firebird in 2 minutes
Migration from MS SQL to Firebird
Public documentation license
Setting up Firebird on Ubuntu Linux
Setting up PHP and Firebird on Linux