It’s been a rough century for the Cubs. They haven’t won a World Series since 1908, and they haven’t captured a pennant since 1945. They’ve punctuated that dry spell with agonizing collapses — their late-season fade in 1969, a squandered 2-0 lead in a best-of-five championship series in 1984, and the Steve Bartman debacle in 2003. History has not been kind, but at long last, this may finally be the Cubs’ year.

On the surface, the team appears to be a solid contender, improved off of last year’s NL Central-winning 85-77 record. Their two-game lead in the division isn’t overly generous, and at 28-18, they trail the Diamondbacks by half a game for the league’s best record. But thanks to a recent 9-2 run in which they’ve outscored opponents 67-35, they have the best run differential through Tuesday, at +74 runs.

Leading the way for the Cubs is an offensive juggernaut that’s scoring a major-league-best 5.7 runs per game while hitting .285 AVG/.371 OBA/.448 SLG, topping the NL in the first two categories and second in the latter. Left fielder Alfonso Soriano has powered the recent streak with a 21-for-44 tear that included seven homers in six games, but he’s had plenty of help. The Cubs are getting above-average production at every position except center field, with first baseman Derrek Lee, second baseman Mark DeRosa, third baseman Aramis Ramirez, right fielder Kosuke Fukudome, and shortstop Ryan Theriot all getting on base at more than a .400 clip.

On-base percentage is the offensive statistic which best correlates with run scoring, and historically, it’s been an Achilles’ heel for the Cubs. Under skipper Lou Piniella, last year’s unit ranked ninth in the league with a .333 OBP, but that was up from a dead-last .319 mark in former manager Dusty Baker’s final year. This year’s offense has been bolstered by the additions of Geovany Soto, a top catching prospect who hit a searing .353/.424/.652 at Triple-A Iowa last year, and Fukudome, an import who topped a .430 OBA in the Japanese Pacific League in each of the last three years.

Meanwhile, the pitching staff has allowed just 4.1 runs a game, third-best in the league, though smoke and mirrors appear to be part of their arsenal. Ace Carlos Zambrano, 6-1 with a 2.45 ERA, is living up to his recent five-year, $91.5 million extension, but while Ryan Dempster’s numbers appear comparable (5-2, 2.70), the latter has relied upon a .218 batting average on balls in play, 76 points below the league average and ripe for serious correction (by comparison, Zambrano is at .284). Rounding out the rotation, Ted Lilly has lowered his ERA to 5.14 after an ugly first four starts, but Rich Hill’s control was so awful (18 walks in 19 2/3 innings) that he was shipped out to Iowa on May 3, leaving the Cubs dependent on journeymen such as Jon Lieber and Jason Marquis.

The bullpen has been a study in contrast between smoke-throwing setup man Carlos Marmol and a shaky supporting cast led by closer Kerry Wood. Marmol has whiffed 41 hitters in 29 innings while holding hitters to a .125 batting average. He leads the majors with 2.4 Reliever Expected Wins Added (WXRL), a stat measuring the increment by which a pitcher increased (or decreased) his team’s chances of winning in each plate appearance; late at bats in close games or key situations count significantly more than those early in the game, in blowouts, or with the bases empty. Wood, who blew three out of four save opportunities at one point, has converted his last six opportunities, but his WXRL is right at zero, and the rest of the unit has accumulated just 0.3 WXRL.

What bodes well for the Cubs is the shaky state of the other Central teams. The Cardinals, their closest pursuers, were forecast for just 75 wins by Baseball Prospectus’s PECOTA forecasting system, thanks to a lineup where Albert Pujols is the sole surviving stud from the team’s “stars and scrubs” approach and a makeshift rotation that lacks ace Chris Carpenter (sidelined until July by elbow surgery). Outfielder Ryan Ludwick has outslugged Pujols (12 homers and .754 SLG to 11 homers and .614 SLG) to give the offense an added threat, while converted relievers Todd Wellemeyer, Braden Looper, and Joel Pineiro have provided strong support for Adam Wainwright. But the bullpen, where Jason Isringhausen has blown six saves, ranks last in the league in WXRL at 0.4.

The Astros, currently third in the division, are even less serious big-picture rivals — they were forecast for an even more dismal 72 wins, but they’ve won 14 of 20 after Tuesday night’s victory over the Cubs. Still, ace Roy Oswalt has struggled with a 5.43 ERA — and this is a team that calls Shawn Chacon its no. 2 starter.

Although the Brewers, who finished a close second behind the Cubs at 83-79 last year, figured to have the best shot at unseating the Cubs, they briefly fell into the cellar after a 4-12 skid and rumors of manager Ned Yost’s imminent firing. Season-ending injuries to Chris Capuano and Yovani Gallardo, plus the poorly timed release of Claudio Vargas, have squandered their rotation resource. Add in five blown saves by recently deposed closer Eric Gagne, and you’ve got a recipe for a non-contender.

The Cubs know all too much about non-contention, having spent many a summer baking on a Wrigley Field surface that felt closer to the sun than to the first division. This year’s team may not win the World Series, but if they merely reach the playoffs for a second consecutive year, they’ll have done something no Cubs squad has done in a century. On the north side of Chicago, that might constitute a dynasty.