The bi-annual Frankfurt Auto Show->ke235 is easily the most important in the world, battling with Geneva ->ke228 and Detroit ->ke222 for the most important reveals. A gentleman's agreement sees Frankfurt and Paris ->ke227 alternate every other year, so each can hog the limelight and be the year's prime spectacle -- larger than any other traveling circus in history.

The reason it is so critical is that it is able to draw a huge number of the world's best automakers, suppliers, tech partners and executives in one place. Even as shows in Asia and lifestyle/hybrid launches in Los Angeles gain momentum, typically nothing compares with Frankfurt in terms of volume of new models, debuts and concepts->ke169.

For competitive insights and also a great look at the current agenda of the global auto industry, there is no better place than Germany->ke2091 in mid-September. Its overlap with Oktoberfest -- in September, despite its name -- allows the best time to soak up the local culture of beer gardens, honeybees, pretzels and roaring Deutsch laughter.

Feet will ache from hours wandering circles in this massive expo center. Despite being mostly an open floor plan, the importance of the show means the manufacturer stands are two and three-story buildings assembled inside. By conservative estimates, this two-week event will cost a major player like BMW Group->ke178 over $35 million in planning, design, signage, stages, turn-tables, media displays, etc. once the crowds have left.

This makes walking around seem like visiting a very crowded future IKEA, but instead of desk lamps, Frankfurt->ke235 is all about concept cars, booth babes and Porsche->ke1 posters. This giant automotive candy store is massive, though, so wear your most comfortable walking shoes and get ready for some warm beers! The show runs from September 12th through the 22nd for the general public and the press days run from September 10th through 11th.

Come join the fun after the jump for the full Frankfurt 2013 Auto Show preview, with a full list of manufacturers on display and the special concepts they will reveal.

Frankfurt Auto Show 2013 Preview - Possible and Expected New Car Debuts

How important is Frankfurt->ke235's auto show? In the past, hundreds of roving guests of unknown languages and countries of origin are seen taking (literally) thousands of ultra-high-res images of all the BMW->ke178, Audi->ke14 and Mercedes->ke187 models: every inch of the dimensions, interiors, paints and panel gaps, everything is sampled and recorded.

No other auto show on the calendar brings out the same level of ferocious automotive intelligence gathering.

Among the 100-plus exhibitors attending the Frankfurt IAA this year, there are nearly 50 very important press conferences scheduled by all the world's most important car brands.

Generally, a press conference means you at least have one new car or concept to debut as a newsworthy item. The 15-minute time slots are just enough to be stunning by a new concept car before the herd moves to the next big debut.

Frankfurt Auto Show 2013 Preview - Possible and Expected New Car Debuts:

- Aston-Martin: Rapide S by Bertone, CC100, One-77, Two-77 Speedster (possible), Lagonda Vignale SUV concept (possible), Vanquish Volante, Vantage S, Rapide Hydrogen

- Audi: A8 facelift, A8 Hybrid, Q7 facelift (possible), Q8, Q6, TT (possible), Quattro Coupe, A3 Sedan, A4 facelift (possible),

- Bentley: Launch debut of 2015 SUV, codename Falcon

- BMW: i8, i3, X5 eDrive, Concept M4, Z5 concept

- Bugatti: Veyron Grand Sport Vitesse, Super Sport and Grand Sport; Concept 16C superlimo possible

- Cadillac: Escalade debut (possible), Elmiraj concept, CTS, ATS-V (possible), ATS Coupe (possible)

- Chevrolet: Camaro Convertible, Corvette Stingray, Orlando facelift, Trax update, Spark EV

- Citroen: DS9 concept, Wild Rubis euro debut as DS5 Crossover, DS3 special editions and update

- Ferrari: LaFerrari, 458 Speciale, FF, F12

- Fiat: 500L Living, 500L, 500 EV, Panda 4x4 and Trekking

- Ford: 2014 1/2 Mustang concept possible, European-market Mondeo debut, S-MAX concept, 2015 Edge concept

- Honda: NSX, Urban SUV Concept, Jazz replacement, Civic updates, CR-V hybrid possible debut

- Hyundai: Concept luxury limo debut, a large cabrio concept possible as well

- Infiniti: Q30 debut, Q50 diesel launch, EV Concept, 2017 Flagship concept

- Jaguar: XQ-type crosover concept debut, Q-type compact sedan concept possible, F-type coupe

- Kia: new K9 luxury debut, crossover concepts and Veloster R possible

- Lamborghini: Cabrera debut

- Land Rover: Range Rover Hybrid, Range Rover Sport Hybrid, Evoque ragtop possible, Defender DC110 concept possible, LR4 Discovery facelift

- Lexus: LF-NX compact crossover debut, GX 460 facelift

- Maserati: Ghibli sedan, Quattroporte, Quattroporte LWB possible, Levante SUV debut, GranTurismo Corsa possible

- Mazda: Mazda3 world debut, 2015 MX-5 roadster concept likely

- Mercedes-Benz and smart: S-Class LWD and AMG debuts, new C-Class, SLC super coupe concept likely, GLA world debut

- Nissan: Maxima concept possible, Juke Nismo, Rogue/Qashqai (cashcow) world debut, sub-370Z EV sports concept, Micra facelift, Pathfinder European debut, X-trail/Xterra facelift possible, Nissan Note (Invitation) production debut

- Opel: Country Tourer, Insignia OPC SuperSport, Adam Black and white, Monza concept (pictured)

- Peugeot: 208 GTiR concept, Pikes Peak Hillclimb 208, 908 HDI FAP LeMans, 408 budget sedan, Crossover concept

- Porsche: Panamera Turbo debut likely, 929 sports coupe possible, world production debut of 918 Spyder, 911 S E-Hybrid, Cayenne S E-Hybrid, Macan world debut, Cayenne facelift, Cayman GT3 concept possible

- Renault: Espace Crossover concept likely, new rear-engined Clio world debut likely, ZOE cabrio, Twizy refresh, Latitude EV sedan refresh

- Seat: Crossover concept, Leon SC and ST, Ibiza refresh, Toledo facelift

- Skoda: 2015 Roomster debut likely, Octavia vRS and Estate, Superb facelift and crossover variant concept

- Suzuki: New Swift 5-door debut

- Tesla Model X concept, Model S, Model Z roadster concept

- Toyota: Hybrid R concept, Prius concept, Auris refresh, Land Cruiser Prado refresh, iQ facelift and updates

- Volkswagen: eGolf, eUp!, CrossBlue SUV debut and rename (likely), Taigun (likely), Golf R confirmed debut

- Volvo: XC90 replacement, Concept Coupe world debuts confirmed

Frankfurt Auto Show 2013 Preview - Press Conference Schedule

A few of the press conferences overlap and are not nearby one another, so take some time with this floor map to get your bearings if you get lost.

Conclusion

So, as much as a consumer showcase to sit in all the latest cars, Frankfurt is also the place to learn how the best cars are built and marketed to consumers. The Monza concept from Opel in the title image shows how powerful concept cars can be in defining a brand's future success potential. Design, branding and technology are becoming quite intertwined.

What if that Monza coupe were to go on sale tomorrow with a Chinese brand name on it? However implausible and perhaps impossible some concept cars are, even considering the thought is part of all auto shows' charms.

The suspension of disbelief from seeing all these cool cars in one place makes anything seem possible in the car world. In Frankfurt, almost anything is possible.