Barry Bonds is Major League Baseball's home run king, holding the records for most homers in a single season, and for an entire career. He is also suspected by many to be a cheater. Beginning in his mid-30s — the twilight of most sluggers' careers — Bonds produced eye-poppingly outsized numbers, while his body and head swelled to comic-book proportions. Before retiring in 2007, Bonds was dogged not only by investigative reports and books about his alleged steroid use, but by a federal government probe centering around his testimony before a grand jury in 2003. This week, the federal trial against Barry Bonds is finally underway. Here, a brief guide:

What is Bonds charged with?
He's not charged with taking steroids. Instead, he faces perjury and obstruction of justice charges for telling a grand jury in 2003 that he had never knowingly ingested the banned substances. If convicted, he could face up to 10 years in prison and a $250,000 fine. He has pleaded not guilty.

What was that 2003 trial about?
At the time, the federal government was investigating the drug company Bay Area Laboratory Co-Operative (BALCO), which was founded by businessman Victor Conte. BALCO distributed performance-enhancing substances like human growth hormone to athletes including sprinter Marion Jones, football player Bill Romanowski, and baseball star Jason Giambi, who testified that he received steroids from a trainer named Greg Anderson — Barry Bonds' personal strength trainer. Bonds claimed that he had no idea Anderson was providing him with anything illegal. Conte and Anderson have both already served brief prison sentences.

What chance does Bonds have of escaping punishment?
That's an open question. Anderson is the key to the government's case against Bonds, and he refuses to testify. "Greg's adamant that he's never going to cooperate with these prosecutors and this prosecution," his lawyer Mark Geragos said on Tuesday. Anderson was ordered into federal custody this week for his refusal to talk, after he had already served 14 months on account of his silence. "Without Greg Anderson's testimony," says Rob Iracane at Yahoo!, "the government is stuck with only three witnesses with an axe to grind on Barry's smooth head —  an ex-girlfriend who posed for Playboy, and a brother and sister who Bonds accused of forging autographs." Prosecutors still think they have enough proof to nail Bonds, but some commentators are less sure. Plus, even if he is convicted, he might escape without an actual prison sentence.

What has happened in the case so far?
Jury selection wrapped up on Tuesday, with eight men and four women — most of whom are not baseball fans — ready to decide Bonds' fate. In their questioning of the jurors, says Lester Munson at ESPN, prosecutors revealed their concern about attacking "a hometown hero on a steroids issue on which many fans have made their own conclusions," while defense lawyers indicated they'll raise doubts about he reliability of government witnesses. The trial is expected to last between two to four weeks.

And the court of public opinion?
Americans are fatigued. The steroid explosion in baseball was once shocking, but now it seems like "old news," says Stephen Brunt at the Toronto Globe and Mail. ESPN's Bill Simmons put it more succinctly: "Wake me when there's a verdict."

Sources: New York Times, The Globe and Mail, San Jose Mercury News, CBS, Telegraph, Business Insider, ESPN, New York Daily News, Yahoo!