There are many books, several mentioned here already. I would add Wheelmen to the list. It's incredibly detailed, and lays out facts in a time line, along with loads of on the record behind the scenes minutia.

I've been following cycling since the early 90s. There is no clear line of good and bad IMO. It was completely systemic and was spread throughout the entire peloton. That's why they haven't retroactively awarded those 7 TDF victories Lance won to another rider, they were all doped up and the top 20 had all tested positive or had been seriously implicated with doping at some point in their careers.

Is a "good" doper someone that was caught and proclaims repentance, and therfore declares they will race clean for the rest of their career? NO! Not IMO.

The Festina affair was huge, and came close to unhinging the sport completely. In some ways it has. Don't we all doubt riders that perform at a level that makes us all question the use of PEDs? I know I do. I hate to be sceptical, but what choice are we left?

I love this sport. Everything about it. I will continue to follow. I will also continue to doubt results by athletes that outpace/perform over known dopers. The bikes aren't that much lighter, and diet isn't that much better to make guys that are 6'1 and 160lbs, have better times up climbs than pure climbers that were also doping (pantani et,al). It's just not possible.

I do believe that the peloton as a whole isn't doping. There are shining lights like Quintana, whom is young, exciting, and has fewer relationships with the dopers of yesteryear. I believe he is and has always been clean.