This in-depth history of the Memorial Day Massacre brings new clarity to the conflicting reports that left too many questions unanswered.   A violent period of American labor history reached its bloody apex in 1937 when rattled Chicago police shot, clubbed, and gassed a group of men, women, and children attempting to picket Republic Steel’s South Chicago plant. Ten died and over one hundred were wounded in what became known as the Memorial Day Massacre.   A newsreel camera captured about eight minutes of the confrontation, yet local and congressional investigations amazingly reached opposite conclusions about what happened and why. Now Chicago historian John Hogan sifts through the conflicting reports of all those entangled in that fateful day, including union leaders, news reporters, and an undercover National Guard observer revealed after seventy-six years.