Firebird! America's Premier Performance Car: The Complete History, by Gary L. Witzenburg. An Automobile Quarterly Marque History Book. Princeton, N.J.: Princeton Publishing Inc. $29.95.

Next fall Pontiac will unveil its long-touted P-car, a 2-seater called Fiero. The midengine sports job is expected to lift the Pontiac car division out of its rut and give it a now-sought-after ''performance image'' for the mid- and late 1980s.

But despite all the early-on interest in Fiero, Pontiac has long marketed another car that caught the performance buff's fancy - and never really lost it.

Witzenburg's book is perhaps the most wide-ranging, behind-the-scenes look at the early and continuing planning and execution of the Pontiac Motor Division's premier sports car, the Firebird. Right from the start, the author combs through the thinking process that produced the car, why it was built, and where it has gone during its years on the road.

The book includes photos of every production Firebird, Pontiac's version of the Chevrolet Camaro, and traces John Z. De Lorean's role in its birth. De Lorean, whose De Lorean Motor Company collapsed last fall, was head of the Pontiac division during the planning stages of the car. He later went on to head Chevrolet.

The Firebird was introduced in midwinter 1967, a new and better version in 1970, and by the mid-1970s dominated the pony-car market in the US.

For the Firebird buff, there are hundreds of photos, some in full color, plus appendices that include every Firebird engine, year by year through 1982, production figures by model year (totaling nearly 1.2 million), sales records, paint colors and codes, performance-test dates by major automotive magazines, basic specifications, and installation percentages for optional equipment.

Also included is a general index and an index of illustrations.