The book, Modern Combat Aircraft # 25: Northrop F-5 / F-20 tells the complete story of the Northrop light-weight T-28 Trainer, F-5 fighter-bomber and the subsequent all-new F-20 Fighter prototype.  "Modern Combat Aircraft # 25: Northrop F-5 / F-20" traces the early development of the design, the testing and manufacturing phases and reveals how early orders for the F-5 A frequently led to follow-up purchases of the F-5 E.  The development of the T-28 Talon trainer and F-5 fighter & fighter-bomber by Northrop in the mid-1950's was something of a gamble in that no firm request for proposal or prototype development had been received from the U.S. government.  While the T-28 gave the United States Air Force their first supersonic advanced trainer, the need for the fighter variant was almost nonexistant until the United States government decided it was the perfect low-cost, light fighter-bomber for future MAP aid programs.  The various F-5 variants would go on to serve in the air forces of some 30 countries including South Vietnam, Republic of China and the Philippines among many others.  The F-5 also found a home as an aggressor aircraft in the United States Navy's "Top Gun" pilot training program located at Naval Air Station Miramar located in southern California.  Despite this, however, by the 1970s and 1980s it was clear that if Northrop wanted to continue the F-5 bloodline, it would need to do so with a more technologically advanced fighter.  This new fighter, the F-20 Tigershark II powered by a single high-thrust jet engine first flew in 1982 but was never put into production due to limited interest on the part of both the United States Air Force and the air forces of allied countries.  A diverse and involved story, not without its political controversy, the accomplishments of the Northrop T-28 Talon and F-5 Tigershark stands unchallenged to this day.  The major sections of "Modern Combat Aircraft # 25: Northrop F-5 / F-20" are as follows: 1) Preface; 2) Chapter 1 - A Fresh Approach; 3) Chapter 2 - Freedom Fighter; 4) Chapter 3 - White Rocket; 5) Chapter 4 - Fighter Trainer; 6) Chapter 5 - Global Defender; 7) Chapter 6 - Little Tiger; 8) Chapter 7 - Canada's Own; 9) Chapter 8 - Tiger II; 10) Chapter 9 - New Tigers For Old; 11) Chapter 10 - T-bird Talon; 12) Chapter 11 - Supermarket Tigers; 13) Chapter 12 - Make Like A MiG; 14) Chapter 13 - Towards The Next Decade; 15) Chapter 14 - Tigershark; 16) Appendix I - Performance Records; 17) Appendix II - Serial Numbers and 18) Appendix III - Thunderbirds T-28.  In addition to an informative narrative, "Modern Combat Aircraft # 25: Northrop F-5 / F-20" includes the following features: 1) Approximately 131 black and white photographs; 2) 12 color photographs; 3) 8 black and white illustrations; 4) 1 two-page Northrop F-5 / F-20 black and white cut-away illustration with component descriptions and 5) 1 three-view F-20 Tigershark black and white illustration.  This book is 112 pages and is in excellent condition.  The author is Jerry Scutts.  Edition published in 1986.