An overview of the website can be found here.
For a more in-depth description of Player won-lost records, how they are calculated, and who the best players of the past 80 years were in various aspects of Player won-lost records, I have published a book with McFarland, entitled Player Won-Lost Records in Baseball: Measuring Performance in Context.
I gave a presentation to the Chicago chapter of SABR (Society for American Baseball Research) on November 18, 2017. I have posted video of the presentation and follow-up Q-and-A on YouTube. The video runs almost exactly one hour.
Thank you for visiting the site and please come back often!