"The Origin of Harley Quinn"
Originally published in Countdown #10.
"Batgirl: Day One"
Originally published in Badman Adventures #12.
"The Opera"
Originally published in Batman #613.
"Holiday Story"
Originally published in Gotham City Sirens #7.
"Kicked in the Teeth"
Originally published in Suicide Squad (2011) #1.
"Tease"
Originally published in Batman (2011) #13.
"Tug a' War"
Originally published in Harley Quinn (2014) #2.
"Evil Anonymous"
Originally published in Harley Quinn and the Suicide Squad April Fools' Special.
*Get an eyeful of Harley's greatest hits from comics including stories from BATMAN ADVENTURES #12 (Harley's first comics appearance!), BATMAN #613, GOTHAM CITY SIRENS #7, SUICIDE SQUAD #1, BATMAN #13, HARLEY QUINN #21, HARLEY QUINN AND THE SUICIDE SQUAD APRIL FOOL'S SPECIAL #1, and the two-page origin of Harley from COUNTDOWN #10 *Source: dccomics.com