Lewis Hamilton begins the defence of his world championship in Melbourne on Sunday.
The 34-year-old British driver is bidding to win his sixth crown and move to within just one of Michael Schumacher's record.
Here, Press Association Sport takes a look at nine key questions ahead of the new Formula One campaign.
1. Will Lewis Hamilton win the world championship?
How do you improve on perfection? That is the challenge facing Lewis Hamilton this year as he gears up for another assault on the title. The Mercedes star was in the form of his life in 2018 to wrap up the championship with two rounds to spare, and now he has the chance to move to within just one triumph of Michael Schumacher's record. The Briton is the bookmakers' favourite in Melbourne but, with rivals Ferrari appearing to hold the upper hand after testing, Hamilton was not being melodramatic when he suggested this could prove the toughest battle of his remarkable career yet.
2. Who is poised to be Hamilton's closest challenger?
Just three thousandths of a second separated Ferrari's Sebastian Vettel and Hamilton after eight days of testing in Barcelona, but the paddock consensus is that it is the red cars, and not the Silver Arrows, which have the best package in 2019. We are used to seeing a Mercedes car top the time sheets in pre-season running but that was not the case this year, and it seems that the world champions are playing catch-up on their Italian rivals. Red Bull will be powered by Honda, rather than Renault this season, and fans of the hugely talented Max Verstappen will hope they have made enough of a step forward to take the fight to Mercedes and Ferrari.
3. Is this a make-or-break year for Vettel?
It is peculiar that we should question the credentials of a four-time world champion, but such was Vettel's second-half collapse in 2018 the German has a point to prove this term. For all of Hamilton's brilliance last year, Vettel and his Ferrari team were guilty of making a series of mistakes. There have since been changes over the winter at Maranello. Team principal Maurizio Arrivabene has been replaced by Mattia Binotto, while the talented Charles Leclerc takes over from Kimi Raikkonen. The young Monegasque could prove the making, or indeed, breaking of Vettel this year.
4. Will Red Bull prove to be contenders?
Daniel Ricciardo has left Red Bull to join Renault, leaving Verstappen to spearhead the team's charge in 2019. Verstappen, still only 21, was in brilliant form at the end of last season with only Hamilton scoring more points than the Dutchman in the second half of the campaign. The Renault engine in the back of the Red Bull last year was sluggish and unreliable, and the former world champions believe a switch to Honda power could help them fight for their first world title since 2013.
5. Who are the new Brits on the grid this year?
There is a real buzz around the two British novices set to make their debuts in Melbourne. George Russell from King's Lynn, Norfolk, arrives on the grid as the reigning champion of Formula Two, the feeder series to F1, as well as having a year under his belt as understudy to Hamilton as a Mercedes reserve driver. Lando Norris, who finished as a runner-up to Russell last season, will become the youngest British F1 driver aged just 19. Russell faces an uphill battle at Williams, however, after their disastrous pre-season campaign, while Norris will race for a McLaren team in transition after years of failure.
6. Can McLaren reverse their fortunes?
McLaren shot themselves in the foot last year by claiming a divorce from engine manufacturer Honda and a new partnership with Renault which was meant to herald in a new era for Britain's most successful team. It did not. Racing director Eric Boullier was sacked, Fernando Alonso has moved on, and Norris and Carlos Sainz form a new-look partnership this season. Andreas Seidl has subsequently been hired to lead the team's F1 project while engineer James Key will start work this month after he was poached from Toro Rosso. McLaren hope this will be the start of a path back to their former glories, but if little to no progress is shown expect American chief executive Zak Brown's position to be under threat.
7. And what about Williams?
There was a period in F1 when McLaren and Williams ran the show, but while the former hope to have stalled their decline, the latter are a team in freefall. Williams finished rooted to the foot of the constructors' championship last year and then did not get their car ready in time for testing, missing the first two days. Robert Kubica completes one of sport's remarkable stories, returning to the grid eight years on from a rallying crash which nearly cost him his life. But expect the Pole and English team-mate Russell to be sparring at the back of the pack, with the British team some two seconds off the pace in testing.
8. Are there any big changes to the cars this season?
The front and rear wings have been simplified and are wider and higher this year in the hope that it will be easier for cars to follow and thus spice up the racing. There is also five kilograms of fuel available so drivers can push harder and longer, while the maximum weight limit has been increased to 80kg to help the taller drivers.
9. What else do I need to know about?
There are no new races in 2019 with the calendar staying at 21 rounds, but the British Grand Prix is set to be the last staged at Silverstone if a new deal is not renegotiated. The British Racing Drivers' Club – owners of the Northamptonshire circuit – are hopeful of getting a deal over the line, while F1's owners Liberty Media do not want to lose a race that has been an ever-present on the calendar. But do not be surprised if the saga rumbles on until the end of the year. Incidentally, the Silverstone race in July will be the only F1 round shown live on terrestrial TV this year after Sky Sports won the exclusive broadcasting rights in the UK.