It was a simpler time, when wars lasted about an hour, ships did not have the "refits" that covered their flaws and complicated their tactics, and a captain with some guts could get things taken care of before the admirals got involved (and in the way). Not that a visiting commodore couldn't stop by and accidentally start a war now and then!
So join us for a simpler time, and a cleaner fight, with ships that exploit each others' flaws with finesse, not brute force, with maneuver instead of overwhelming head-on attacks.
This time period lasts from Y125 (2525 by the Valkenburg Chronology) to the Four Powers War. It is covered in Star Fleet Battles BASIC SET by the ships without the refits. It is also covered in Federation Commander Briefing #2.