Writer Colum McCann has described as "shocking and cowardly" the attack on him in the US state of Connecticut, which left him with severe concussion, a broken cheekbone and some broken teeth.
In a statement, Mr McCann said he was also left with a spirit that was temporarily bruised, but that he is recovering quickly.
The attack happened in New Haven, Connecticut, where the author was visiting ahead of delivering a keynote speech at a local university.
A man and a woman were involved in a dispute on a street in the city at around 10pm.
Mr McCann is understood to have intervened to assist the woman, and the man then punched him in the face.
New Haven police earlier said they had "significant leads" in the case and are "hopeful of an arrest sooner rather than later".
It is understood they know the attacker's identity but not his whereabouts.
Mr McCann said he has been overwhelmed by the generous response from friends and strangers alike.
The fact that it happened on the edge of one of the world's foremost colleges highlights how prevalent this sort of situation is, he added.
Mr McCann is the author of six novels but is best known for his 2009 novel 'Let the Great World Spin'.
He was in New Haven to speak at the Southern Connecticut State University with a teacher from Newtown High School where students have been studying the book to deal with their grief following the shooting at the nearby Sandy Hook elementary school in December 2012.