"Terry is a very private woman who gives little away," said one acquaintance. "She is always cool, calm and collected."
But even that renowned sang froid must have been sorely tested in a week which has seen the self-effacing Professor Rees thrust into the media spotlight after the Welsh Assembly's debate on tuition fees was held just two days before yesterday's publication of the Rees review.
Fearing that her group's 18 months of hard work could be wasted, Professor Rees took the unprecedented step of writing to Assembly members, urging them to reconsider their position (see story above), after publicly criticising Welsh Conservatives for tabling an Assembly motion restating opposition to top-up fees almost before the ink on her report was dry.
Professor David Reynolds, of Exeter university, feels Professor Rees's qualities made her the right person for the job.
"She is a balanced, rational person with no axe to grind who will reach judgements on the evidence as she sees it," he said. "She was therefore the ideal kind of person to produce this report."
The mother of two sons, Professor Rees is a pro-vice-chancellor of Cardiff university, responsible for staff and student issues, and a professor in the school of social sciences. Extremely committed to women's issues - she was equal opportunities commissioner for Wales from 1996 to 2002 - she has a distinguished record of research and consultancy on gender equality in fields such as education, training and the labour market.
Dr David Grant, vice-chancellor at Cardiff university, said: "Her research has underpinned many substantive shifts in approach to gender equality and equal pay. Her commitment to equal opportunities has had direct and real benefits for women in Wales and further afield.
"Professor Rees makes an impact through reasoned argument and influence on policy-makers, and those who can make a difference for women."