THERE ARE about 15,000 parts in a typical car. Several years ago, those parts were specifically similar enough that generic car repair books became popular. One book for all was the theory.

Lots of aspirants are still trying to write the consumer auto repair book. Any self-respecting bookstore's automotive section is heavily biased toward these do-it-yourself guides. Books of automotive history or commentary, while available, are infrequently stocked. Looking at the shelves a browser would think that the only books about cars deal with fixing the infernal machine.

The complexity of the modern automobile dissuades neither budding or fully bloomed authors nor neophyte mechanics from a frontal attack. The safety implications of an improperly-done brake or steering repair fazes neither. Despite this danger and the direct threat of serious personal injury, both sides plod onward seeking the book.

The Complete Car Care Manual from Reader's Digest ($19.95) is the newest book on the auto repair shelves, baked in the same mold as their earlier Do-It-Yourself Manual and Home Repair Manual . It's so new that it's not expected in stores until near the end of the summer.

Being a new entrant has its advantages, such as scouting the competition. The multi-colored line drawings instantly set this book apart from the others. You won't see illustrations of this quality elsewhere.

The CCM does something important: it rates the difficulty of each repair, and it provides a guide to the time the procedure may take. The ratings are all too honest, because few of the repairs are rated for novices with no previous experience. In the CCM 's rating system, a novice is the lowest of five experience grades.

Reader's Digest offers more than a repair manual with the CCM . It's a car owner's manual, meant to take the intimidation out of the automobile's complexity. A good book for the new, young driver in the family, or as the whole family's reference on things automotive.

One-of-a-kind illustrations of another design, and informal language, distinguish the two Volkswagen books from John Muir Publications, How to Keep Your Volkswagen Alive ($11) and How to Keep Your Volkswagen Rabbit Alive ($13). Art by Peter Aschwanden combines humor with technically accurate illustration's in both books, the first one covering air-cooled Beetles; and the second, the newer Rabbits, a very different VW animal.

Muir is the original champion of the Beetle as a simple basic car that, given a modicum of care with ordinary tools and skill, will be a friend for life. Now in its 24th printing since 1969, it survives unusually well for an auto repair book, a tribute to air-cooled VW's, as much as it is to Muir. It shows its early birthdate principally in obsolete terminology like "HD" motor oils. Muir is strongly opinionated and that gets him into troubles at times, but he does fervently preach the gospel of frequent attention to minor maintenance to avoid major repairs later.

The Rabbit version of VW Alive is authored by Richard Sealey, clearly a Muir disciple. This book is less successful than the original. Sealey imitates Muir's style, but Rabbits are more complex than Beetles, whether considered zoologically or automotively, and that complexity causes a number of Sealey's suggested Rabbit repairs to exceed the skills of many novices and even experienced amateurs.

The informal language and Aschwanden art may turn off traditionalists, but Muir's VW books, especially the Beetle book, are proven products. Intriguing enough to get the reader to buy a Volkswagen if he doesn't already have one!

As an option, the Beetle book is also available in German and Spanish language editions that omit only the models with fuel injection.

Paul Weissler's Weekend Mechanic's Handbook: Complete Auto Repairs You Can Make (Arco, $8.95) looks inviting on the bookstore shelf with its bright attractive cover. Numerous photos taken especially for the text, and supplemented only where necessary with supplier's illustrations, are its strong point. Weissler is knowledgeable but his task seems too great for him to be anything other than general in treatment.

Deanna Sclar in her Auto Repair for Dummies (McGraw-Hill, $8.95) relates how she got started in repairing her own car, "I conned a friend of mine who happened to have two sets of car tools into taking an auto shop class with me at a local adult education center," but she failed to appreciate the value of this training and doesn't recommend that others seek auto repair knowledge in the same way: through a formal class. The credit lines on the illustrations read like commercials for marketers of replacement auto parts. Readability is not Sclar's downfall; facts get botched that her technical adviser, Don Donesley, should have caught in editing. ARD needs revision since its 1976 publishing date.

If John Muir had a mentor, it was possibly Dick O'Kane whom auto enthusiasts remember for his book on imported car repair when imported cars were still a curiosity. Simple Car Repair (Doubleday, $2.95) is not vintage O'Kane, but it's enjoyable and to the point.

The reader gets mostly works from O'Kane, and pictures are needed in auto repair manuals. Light-hearted reading, but not particularly helpful.

Petersen Publishing Company, the big automotive magazine and specialty book publisher, presents its Big Book of Auto Repair ($14.95). It deals only with an American car's main operating systems (engines, transmissions, carburetors, ignitions) in a manner for advanced amateurs only. There is no help here for the novice.

Much more helpful is Petersen's How to Tune Your Car ($4.95). It has step-by-step tune-ups for various American cars with photos of specific details. Coverage is limited, and newer cars are not included, but if your car is among those detailed, How to Tune Your Car would be a good supplement to other books.

Petersen also publishes Basic Auto Troubleshooting ($4.95), which provides logical diagnostic procedures for those who have progressed beyond the novice stage. Even over-confident professional mechanics could use it to bring their feet back down to earth and their skills up to date.

Even the government is into auto repair books. No, not the National Highway Traffic Safety Administration's infamous Car Book that some critics feel needs repairs of its own, but The Backyard Mechanic, (U.S. Government Printing Office, $1.60, $1.60, $4), three collections of reprints of auto hobbyist articles from the military magazine, Driver . The Backyard Mechanic reader is often encouraged to tinker and adjust and dismantle things like carburetors that seldom require such obsessive attention. The lack of an index hampers those searching for particular information. Not a best buy, but inexpensive.

The Consumer's Digest Automobile Repair Book (McGraw-Hill, $7.95) by Arthur Darack has many illustrations taken right from the auto maker's own service manuals. You may find an explanation here for your question if the picture matches the part on your car. It probably won't, though, even if it's a Ford, GM, or Chrysler product. There are too many subtle variations in components these days for Darack's pseudo-precise approach to succeed with those just starting out in car repair.

Two books from Gousha-Chek-Chart, Car Service Manual ($8.60) and Tune-Up Service Manual, ($8.35) explain auto parts and systems, but are designed for the professional mechanic. After a broad introduction to the subject through a book like Reader's Digest Complete Car Manual , the Gousha books would make a good second purchase. They don't lead the reader by the hand as the other books do or attempt to do. This is straight-from-the-shoulder information that can help someone desiring in-depth knowledge beyond the basics.

The Complete Handbook of Practical Car Repair (Tab Books, $9.95) and The Complete Book of Car Maintenance and Repair (Scribner's, $14.95) are ordinary efforts. The first by Kenneth F. Lower intimidates with its high ratio of words to pictures. That's a familiar complaint, but especially in this book. The second book by John D. Hirsch is an old book, revised in 1977 and in need of another overhaul, that tries to be a driver's companion as well as a repair guide.

In an overview, most of these introductory books are disappointing. Even basic instruction on the aiming of headlights was repeatedly in error or not mentioned at all. If you're blinded in night driving, you now know why.

Safety advice was minimal, and should have been stressed more, even by Reader's Digest. Biographical information on authors, such as their credentials and experience, was minimal. No help there in choosing a book.

Securing accurate specifications for adjustable components is a major problem in the professional repair industry. For do-it-yourselfers, it is rapidly becoming a mightmare. The most reliable information comes from the car manufacturer: one of his manuals, or a sticker on the car. Any other source should be viewed with suspicion, especially if an imported car is involved. Even the Reader's Digest Tuneup Data supplement is not as accurate as the car care manual itself.

The shortcomings of an individual book are easily rectified; don't buy just one. No single auto repair book can tell beginners enough about this wheeled investment, the family car, although Reader's Digest CCM is a good beginning. If you're serious about doing it yourself, you'll eventually acquire a library of several books.

But the best beginning is to follow Deanna Sclar and take an auto repair class. The supervised on-hands instruction is invaluable, the question-and-answer exchanges essential, and the camaraderie reassuring. Auto repair by the books alone should not be your first step.