Silver Age Sentinels

Silver Age Sentinels is a superhero role-playing game (RPG) published in 2002 by Guardians of Order, creators of "Big Eyes, Small Mouth", an anime-themed RPG. 
History.
Guardians of Order's move into the d20 market began with their new super-hero RPG, "Silver Age Sentinels" (2002), written by Mark C. MacKinnon, Jeff Mackintosh, and Jesse Scoble, with Steve Kenson and developed by Lucien Soulban. "SAS" was produced in two different editions, a Tri-Stat edition in July 2002 and then a d20 edition for GenCon 35. James Lowder's experience packaging fiction for Green Knight Publishing ultimately led him to put together fiction packages for other small companies, including some "Silver Age Sentinels" books for Guardians of Order (2003-2004). After Guardians of Order went out of business in 2006, White Wolf bought the IPs for some of the company's games, including "Silver Age Sentinels". Their ArtHaus imprint holds the rights to "SAS".
Description.
"Silver Age Sentinels" features an original game world inspired by classic "four-color" DC and Marvel comic book series, updated to modern political and moral sensibilities. The Empire City Universe (referred to after its central location, an alternative version of New York City) has a distinctive history.
The original system is a variant of the Guardians of Order "Tri-Stat" system, later ported into a generic form called "Tri-Stat dX". It expands the system, adding additional modifiers to allow more customized powers and characters. It also uses the ten-sided die (d10) as its base die as opposed to the six-sided dice (d6) used in Guardians of Order's previous RPG titles.
A "d20" version, using a similar power creation structure modified for compatibility with the "d20 System" line, was released two months after the "Tri-Stat" version. Many of its concepts were adapted to the d20 version of "Big Eyes, Small Mouth".
The original "Deluxe" version is a full color hardcover, while the "Unlimited" version is a hardcover with a full color cover only. "Silver Age Sentinels" "d20 System" version is also hardcover with a black and white pages. The "d20 Stingy Gamer Edition" was softcover.
The game is also the foundation for "The Authority Role-Playing Game", a game based on Warren Ellis's "The Authority". That game features a much higher power level, and uses twelve-sided dice (d12) as its main action resolution.
Two anthologies of creator-copyrighted short stories tied to the SAS universe were published by Guardians of Order. "Path of the Just" (2003) featured an introduction by Denny O'Neil and included stories by John Ostrander, Steven Grant, and Ed Greenwood. "Path of the Bold" (2004) featured an introduction by Elliot S! Maggin and included stories by Robert Weinberg, John Kovalic, and Mike W. Barr. Both anthologies were edited by James Lowder.