Anthony (Tony) Kroch, Professor Emeritus of Linguistics at the University of Pennsylvania, died of cancer at the age of 75 on April 27th in his home in Philadelphia. He was attended by his wife, family, and dedicated caregiver, Joyce Allen. Anthony was born to German Jewish refugees, Adolph and Hilde Kroch, who fled the Nazis following the arrest of his maternal grandfather on Kristallnacht in 1938. His parents, stripped of their citizenship due to the Nuremberg laws, and with no legal immigration path, lived in the United States without status. Under an amnesty in 1945, they re-entered the United States through Canada and were granted permanent residency. Anthony was born in 1946 in New York City, and later that year, his parents were naturalized as US citizens. Anthony was raised in New York City, White Plains, NY, and Needham, Massachusetts, and graduated from Needham High School in 1963. He attended Harvard University, where he was elected to Phi Beta Kappa in his junior year and graduated summa cum laude in Anthropology in 1967. After graduating, he obtained a fellowship to support a year of world travel. Accompanied by his wife Martha, he took the opportunity to live among indigenous people in Brazil and Senegal, and studied the formal narrative structure of their stories and myths. In 1974, Anthony completed his doctoral thesis in linguistics at MIT (under the direction of Professors Paul Kiparsky, Noam Chomsky, and Kenneth Hale). His academic pursuits were punctuated by activism against the Vietnam War and academic racism. He was a member of the Progressive Labor Party and organized student protests in Massachusetts and Connecticut. Following appointments in the Anthropology Departments at the University of Connecticut and Temple University, in 1978, he obtained a fellowship with William Labov at the University of Pennsylvania to conduct sociolinguistic interviews and analyze the language of upper-class Philadelphians. In 1981, Anthony joined the faculty of the Linguistics Department, where he conducted research and taught until his retirement in 2020. Anthony studied the structure of human language using computational and statistical methods. In collaboration with Aravind Joshi of the University of Pennsylvania's Computer Science Department, he applied mathematical formalisms to characterize language. He is best known for his work on historical syntax, demonstrating that grammatical changes over time occur at a constant rate. In collaboration with Beatrice Santorini and others, Anthony pioneered the construction of large annotated databases of historical texts. With Beth Randall, he developed tools to search these corpora. These efforts served as the basis of his research and as models for the construction of corpora in multiple languages. They continue to support a range of linguistic studies. Anthony was known for spirited conversations about linguistics, politics, and everyday life. He is survived by his wife Martha, his brother Eugene, his daughters Miriam (Daniel) Morrissey of Deep River, Connecticut, Deborah (Brian) Leaf of Reston, Virginia, Abigail Kroch (Jason Brenier) of Toronto, Canada, grandchildren Jacob, Katherine, Sarah, Madeline, and Jonah, and beloved niece Michelle Burgess (Raul Mandru) and grandnephew Felix.