FRANCE
Previous World Cup best: Runners-up (1987, 1999, 2011)
Head coach - Philippe Saint-Andre: It would be fair to say that there are not many supporters of the French national side that have faith in Saint-Andre. The 48-year-old took charge in 2012 and since then his record has been miserable. In four Six Nations campaigns, France have finished no higher than fourth under Saint-Andre's watch. Coupled with some unimaginative rugby out on the pitch and it's easy to see why the former Gloucester winger is not the most popular of figures. He will step down at the end of this tournament, yet it's amazing that he's lasted this long.
Key player - Thierry Dusautoir
As captain, Dusautoir showed four years ago that he has the ability to unify a squad, despite plenty of in-fighting. It would appear that if France are to be successful this time around, the 33-year-old is going to have to fight similar fires. He may have only recently returned to the fold following a knee injury, but as one of the hardest hitters in the game - something that he displayed in the quarter-final win over New Zealand in 2007 - his place in the starting lineup must be guaranteed.
Sports Mole says: It's tough to analyse how Le Bleus are going to fare over the next few weeks. You would expect them to advance through the pool, but right now it looks like anyone could give them a game. The last eight would appear to be the limit, though, with their likely opponents - either the All Blacks or Argentina - probably too strong.
IRELAND
Previous World Cup best: Quarter-final (1987, 1991, 1995, 2003, 2011)
Head coach - Joe Schmidt: Is there a coach with a better strike rate than Schmidt? Having won four trophies (including two Heineken Cups) in three seasons with Leinster, the 50-year-old Kiwi has guided Ireland to back-to-back Six Nations titles. Lesser bosses may have struggled to cope with the transition into the post Brian O'Driscoll era, but Schmidt has negotiated the Irish through it with flying colours.
Key player - Jonny Sexton
He may have looked a little rusty in the recent warm-up clashes against Wales and England, yet the fact is that Ireland are still heavily reliant on Sexton. On top form, there is a yawning chasm between the 30-year-old and his fellow number 10s in the squad. The Leinster fly-half has nerves of steel, which often sees him dig his side out of a hole when all hope appears to have been extinguished. This could well be his last World Cup, so Sexton will be looking to go out on a high.
Sports Mole says: The Irish may head into the tournament on the back of two narrow defeats, but that has done little to dampen the optimism among the fans. If anything, there is a belief that Ireland have got their bad performances out of the way early. How far can they go? Getting out of the pool shouldn't be a problem and if they can avoid New Zealand in the quarter-finals, the last four or even the final may not be beyond Schmidt's men.
ITALY
Previous World Cup best: Pool stage (1987, 1991, 1995, 1999, 2003, 2007, 2011)
Head coach - Jacques Brunel: Having guided Perpignan to the Top 14 title in 2009, Brunel took charge of Italy two years later. He then made an immediate impression as the Azzurri recorded a memorable victory over his native France. However, his decision to announce so early that he would be leaving his role after the World Cup has raised a few eyebrows. Results since then have been relatively poor, which some have attributed to the fact that Brunel made his exit public knowledge.
Key player - Michele Campagnaro
The 22-year-old may have been plagued by injuries ever since he made his international breakthrough in 2013, but when he is on the pitch, the centre is a valuable asset for Italy. Wales discovered just how dangerous the Exeter Chiefs player can be when he ran in two tries against them in a memorable display last year. What's more, Venice-born Campagnaro is not one to shirk a tackle.
Sports Mole says: The first eight months of 2015 have been tough for Italy. Not only have they lost three games on the trot, they are also sweating on the fitness of captain and talisman Sergio Parisse, who will almost certainly miss the opening game against France. Their two key games will be against the Irish and the French and in truth, it's highly unlikely that Brunel's men will be able to topple either of them.
CANADA
Previous World Cup best: Quarter-final (1991)
Head coach - Kieran Crowley: The 54-year-old, who played in two World Cups for New Zealand, has been in charge of Canada since 2008. Memorable victories, as you would expect have been at a premium, with Crowley's biggest achievements in the job being the wins over the USA that have secured Canada's place at the last two World Cups.
Key player - Jamie Cudmore
He may have turned 37 earlier this month, yet the experience that Cudmore provides to the Canadian squad is invaluable. The lock has only just returned to fitness, which was a timely boost for Crowley. Any concerns over the injury problems were recently put to bed by the fact that the Clermont Auvergne player played three games in nine days. This will be his fourth, and likely last, appearance at the World Cup.
Sports Mole says: With a number of sevens players likely to be included within the starting XV, there is every chance that Canada will be exposed on a physical level. With concerns over the scrum as well, it's highly possible that the North American nation will be battling to avoid finishing bottom of what is a European dominated pool.
ROMANIA
Previous World Cup best: Pool stage (1987, 1991, 1995, 1999, 2003, 2007, 2011)
Head coach - Lynn Howells: The former Welsh international has a host of coaching experience, starting with his role as the assistant to Wales boss Graham Henry at the 1999 World Cup. Since then the former Pontypridd number eight has taken charge of Cardiff, Celtic Warriors, Edinburgh and Italian outfit Leonessa.
Key player - Florin Vlaicu
With the greatest of respect, tries are not likely to be free flowing for the Romanians. As a result, the Eastern Europeans are going to be extremely reliant on the boot of Vlaicu. Nobody has scored more points for Romania than the 29-year-old, who currently plays his club rugby for CSM Bucuresti.
Sports Mole says: They may not have been in the best form of late, yet the Nations Cup victory back in July will have certainly boosted confidence. The pack has plenty of experience, which could well be enough to get the better of Canada and even cause problems for the Italians. That will be as good as it gets, though, with France and Italy likely to record comfortable victories over Howell's men.
Pool D fixtures
Saturday, September 19
Ireland vs. Canada
France vs. Italy
Wednesday, September 23
France vs. Romania
Saturday, September 26
Italy vs. Canada
Sunday, September 27
Ireland vs. Romania
Thursday, October 1
France vs. Canada
Sunday, October 4
Ireland vs. Italy
Tuesday, October 6
Canada vs. Romania
Sunday, October 11
Italy vs. Romania
France vs. Ireland
Sunday, October 11
USA vs. Japan
Prediction: 1. Ireland 2. France 3. Italy 4. Romania 5 Canada
