[5] As a tech entrepreneur in the 1990s and 2000s, Kirschner launched the National Football League's website, the first online livestream of the Super Bowl,[6] and co-founded Columbia University's interactive knowledge network Fathom.com.

Kirschner started out as a lecturer on Victorian literature at Princeton University and working as a freelance writer for CBS, The New York Times, and Chronicle of Higher Education.

Kirschner has conducted research on doctorates in business, funded by grants from Texas Committee for the Humanities, and the Littauer Foundation to study slave labor camps.

Her start-ups include Request Teletext, the first full-channel cable teletext service;[11] Primetime 24 - the first home satellite broadcast network;[12] NFL Sunday Ticket and NFL.com - the first sports league on satellite television and the Internet; and Fathom.com, one of the first offerings of online learning in higher education to be affiliated with universities, libraries, museums, and research institutions.

The letters include correspondence between Kirschner's mother and Ala Gertner, who was hanged for her role the sonderkommando revolt at Auschwitz.

According to the author, Marcus sparked the world's most famous gunfight, buried her husband in a Jewish cemetery after he died in 1929, and subsequently shaped the legend of Wyatt Earp and the Wild West.