The 2019 Formula 1 season starts in Melbourne this weekend and it promises to be one of the most interesting in years.
The first car has not even turned a wheel in anger and yet there are so many intriguing plot lines right down the grid.
Let's take a look at some of the big questions on the eve of the Australian Grand Prix.
Hamilton v Vettel, Part III
Lewis Hamilton and Mercedes have dominated Formula 1 for the past five years, Hamilton winning four of the last five world titles and his former team-mate Nico Rosberg the other.
But those statistics belie the facts that in 2017 and 2018 Ferrari started the season with an absolutely competitive car and their lead driver Sebastian Vettel should have at least taken the title fight to the last race.
In 2018, Vettel had something of a personal meltdown, making a string of errors which, exacerbated by management failures at Ferrari, saw his season implode and Hamilton win with two races still to go.
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- Australian Grand Prix coverage details
It's all change at Ferrari this year. Their unpopular former team principal Maurizio Arrivabene has gone, and in his place is former technical director Mattia Binotto, renowned as a cool and calm personality who will provide a more stable environment for the team.
And Ferrari have hit the ground running, their car clearly faster in pre-season than the Mercedes, who F1 sporting boss Ross Brawn described as "a little bit out of sorts".
Hamilton himself put the gap between the two cars in performance at as much as half a second a lap, and said: "This is going to be the toughest battle yet."
Can Vettel and Ferrari finally get one over on their great rivals?
How will Leclerc do at Ferrari?
The big question over Vettel may be how he will cope with the pressure of a title fight, after wilting so badly in 2018, but there's another - and that is in the identity of his team-mate.
Kimi Raikkonen - reliable, not-quite-quick-enough - has gone to sister team Alfa Romeo, and in his place has come 21-year-old Charles Leclerc, who is tipped as a star of the future.
There is great anticipation within F1 as to how Leclerc will fare at Ferrari, with many expecting great things of him.
Ferrari have said Vettel will have priority in certain circumstances at the beginning of the year, but if Leclerc proves a match for Vettel how long can they let that carry on, and how will they manage the situation?
The battle inside Ferrari could be as exciting as that between them and Mercedes.
A new era for Red Bull
Red Bull have finally parted company with engine partner Renault after five years of the turbo hybrid engine formula marked by bitterness and recriminations.
In Renault's place has come Honda, who have not exactly set the world on fire since they returned to F1 in 2015. Unless you're talking about how many engines have failed.
Nevertheless, there is optimism at Red Bull that they will be more competitive with a Honda engine than they were with a Renault - and their minimum goal for the season is to be closer to Mercedes and Ferrari than before.
Red Bull did not set any eye-catching times in pre-season testing but their lead driver Max Verstappen, who won two races last year and should have had a third, said he feels "optimistic" about the season ahead.
"If we look to the longer runs, it looks all pretty promising," the Dutchman said, "so, yeah, I'm looking forward to start racing now. I think we have a pretty good package and also the engine seems to work really well. I'm really happy about that."
If Red Bull can get in the mix with Ferrari and Mercedes, the prospects of the fiery, aggressive, uncompromising and very quick Verstappen going toe-to-toe with Hamilton and Vettel are mouth-watering.
A new Brit pack
Hamilton was Britain's sole representative on the grid last year but this season he is joined by two of his countrymen. Well, two and a half, really.
Williams' George Russell and McLaren's Lando Norris arrive in F1 after stellar junior careers. But Toro Rosso's Alexander Albon, who races under the Thai flag but was born in London to a British father and Thai mother, has proved pretty handy himself.
Russell has been part of the Mercedes junior programme for the last two years and has already driven seven F1 cars.
As he puts it: "Three Mercedes, two Force Indias, one Williams and one McLaren, that's quite a surreal little fact. Even now just saying that, it kind of hits me. You think, 'Blimey, that's quite a privilege.' Even though my career's only just started its already been an amazing achievement."
Norris, who finished second to Russell in Formula 2 last year, has excelled in everything he has driven - including alongside Fernando Alonso when they teamed up at the Daytona 24 Hours in 2018.
Albon, who finished third in F2 in 2018, thought his chances of an F1 career were over, and had signed to drive for Nissan in Formula E, only for Red Bull to come calling when they realised they were short of a driver.
All three have spent their junior careers racing against not only each other, but fellow F1 drivers Leclerc, Verstappen and Mercedes reserve Esteban Ocon.
It really is the start of a new generation, with Russell and Norris proving so far to be potentially at the head of it.
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Are Williams that bad?
Even before Williams' new car had run, the omens were not looking good, with stories coming out of the factory that it was two seconds slower than the 2018 car - already the slowest on the grid.
When it missed the first two and a half days of testing because it wasn't ready, things looked even worse, and when it finally did hit the track, they didn't look much better. It was slowest of all throughout winter testing.
To sum the field up on the eve of the season, Ferrari look to be in front, Mercedes and Red Bull closely matched not far behind, the midfield appears not only to have closed the gap to the big three, but to have compressed within itself - and then there is Williams.
Heading into Melbourne, the question about Williams appears to be not so much are they at the back, as how far off the back are they?
This would be a real shame, not only for Russell, but also his team-mate Robert Kubica, whose return to F1 after eight years out following the life-changing injuries he suffered in a rally crash in 2011 is one of the stories of the season.
But it's also terrible news for Williams, former multiple championship winners who appear to have completely lost their way.
All times GMT and are subject to change at short notice.
|Australian Grand Prix coverage details|
|Date||Session||Time||Radio coverage||Online text commentary|
|Thursday, 14 March||Preview||21:00-22:00||BBC Radio 5 Live|
|Friday, 15 March||First practice||00:55-02:35||BBC Radio 5 Live Sports Extra||From 00:30|
|Second practice||04:55-06:35||BBC Radio 5 Live Sports Extra||From 04:30|
|Saturday, 16 March||Third practice||02:55-04:05||BBC Radio 5 Live Sports Extra||From 02:30|
|Qualifying||05:55-07:05||BBC Radio 5 Live Sports Extra||From 05:30|
|Sunday, 17 March||Race||04:30-07:00||BBC Radio 5 Live||From 03:40|
|Monday, 18 March||Review||04:30-05:00||BBC Radio 5 Live|
|F1 podcast: Australian Grand Prix Preview||Download here|