George Dobell is a senior correspondent at ESPNcricinfo
These are puzzling times in English cricket.
While the drawn Test series in the Caribbean was hailed a "disaster" by one commentator, the drawn Test series at home against New Zealand was hailed "wonderful."
And while England's limited-overs success against New Zealand was encouraging, it seems premature to label it a new age. It came, after all, against a side which, by the end, was without four of the first choice attack that took them to the World Cup final.
It has been heartening to see the outpouring of support for England in recent weeks. To see grounds full - or all but full - for ODIs is one thing; to see crowds gripped by thrilling cricket - England's thrilling cricket - has been more heartening still. It has been many years - maybe as many as 10 - since the feel-good factor in English cricket has been so high.
So it seems churlish to point out that this England side was humiliated in the World Cup only three or four months ago. It seems churlish to point out that the last Ashes series ended in a whitewash defeat and that only one of the last five Test series has been won.
The truth is, this young England side has huge potential. But it is, as yet, unfulfilled.
This Investec Ashes series may well come a little early in their development cycle. Many are still learning their way at this level: Jos Buttler has yet to make a Test century; Mark Wood and Adam Lyth have played only two Tests each and Joe Root and Gary Ballance, for all their excellence over the last 18-months, know that this is the opposition that will define them as Test players. Australia are favourites. It should not be doubted.
But England can win. If they can find the consistency to complement the flashes of brilliance they have shown in recent times, if they can replicate the bravery of their talk with the audacity of their action.
Here we look at the key areas where England need to perform if they are to win:
It is a dim memory now but, at the start of their World Cup campaign, Chris Woakes dropped Aaron Finch at square leg before he had scored. There was little in England's cricket afterwards to suggest it was a defining moment, but who knows? Finch went on to score a century and the belief ebbed out of England.
The point is, if England are going to have any chance of success in this series, they are going to have to take more catches than they have in recent months. At one stage against New Zealand, at Headingley, they missed three chances in eight balls. It seems unthinkable that England's bowlers will create so many chances that such profligacy will go unpunished.
The cordon behind the stumps has been most fallible of late. Buttler, for all his flair with the bat, remains a work in progress with the gloves, while Ian Bell endured a tough time against New Zealand.
Evidence suggests England will retain faith in the same fielders in the same positions. If that leads to the same results, the Ashes will be lost.
By the end of the series against India, it seemed Moeen Ali had won over his critics. His deceptively quick offspin, benefiting from lovely drift and sharp dip, proved effective against some of the best players of spin in the world and played a huge role in England coming from behind to take the series.
A few months on, however, he is on trial again. Two modest Tests in the Caribbean and two more against New Zealand - albeit four modest Tests which realised a far from disastrous 11 wickets at an average of 41.63 - and he is again finding himself described as a "part time" bowler. Ironically, the man who many suggest as his replacement - Adil Rashid - has bowled fewer overs and taken fewer wickets at a higher average than Moeen in first-class cricket since the start of 2012. England are not over burdened with spin bowling choices at present.
Still, Moeen will have to bowl far better than he managed in those four Tests if England are to prevail. If he drops as short as he did in Barbados, he will be hit out of the attack and England will be stuck with four right-arm seamers and little hope of capitalising on worn surfaces. If he rediscovers the consistency and bite he found against India, he will cause damage. So far this summer, he has struggled to keep an end tight.
Either way, he will be given plenty of opportunity. Not only will Australia come at him - they appear to see him as a weak link - but they will probably play two left-arm seamers in their side, which should create rough outside the right-handers off stump to encourage both Moeen and Nathan Lyon.
How Moeen fares will go a long way towards deciding the fate of the Ashes.
Cook has played five series against Australian. In one of them he averaged 127; in the other four, he averaged a maximum of 27. He appears to be back to his best in recent Tests, but the Australia attack represents a sterner challenge.
How he comes through it will have a huge bearing on the series. If England's largely young middle-order is to be given the best chance to prosper, they require some protection from the new ball and some foundations on which to build.
With an inexperienced opening partner in Lyth, a No. 3 with some questions to answer in Ballance and a No. 4, in Bell, who is coming into this series on the back of some low scores, there is need for Cook to score heavily if the stroke-makers are to be given a decent chance.
There has been much talk about the positive cricket England are going to play of late. And that is all well and good: they have a side that, in several cases - Buttler, Moeen, Wood, Stokes - would appear to be at its best when it playing aggressively.
But all such talk will be meaningless if the sides are not given the chance to play attractive cricket by the surfaces. If, as feared, the surfaces are low, slow and flat it will not only negate the Australian pace bowlers, it will negate the England ones and the batsmen of both sides who like the ball coming on to the bat. It will make it almost impossible to play bright, positive cricket and reduce this series - like the one in 2013 - to a war of attrition.
That's okay. But if England really are committed to the aggressive approach we keep hearing about, they need to convey that message to the groundsmen.
All the evidence suggests that the pitch in Cardiff will be slow, flat and - though the authorities deny it - designed to ensure five days of ticket sales. It would be a betrayal of England's ethos if so.
James Anderson and Stuart Broad will have to use to new ball effectively if England are to win. In recent times, the first new ball has often been squandered as the pair ease their way into games. Perhaps wearied from previous exertions, perhaps saving themselves for future ones, the pair have often bowled at a relatively gentle pace early on and then sought to pick up the pace when they sense key phases of the match.
While such an approach is understandable - no two seamers have bowled more in international cricket since 2010 - it runs the risk of allowing batsmen to settle against them.
Both men have tended to bowl back of a good length in recent times, too. While such a tactic has a place - especially when the wicket is flat and the intent is to frustrate batsmen - when the ball is new and conditions at their most helpful, Broad and Anderson have to force the batsmen to play more often by bowling deliveries that would hit the top of the stumps.
Wood and Stokes are exciting talents who could well change a game or two in this series. But it seems likely that, if England are to win the Ashes, either Anderson or Broad will have to be their side's top wicket taker.
Australia tour of England and Ireland