I was born in Frederiksberg near Copenhagen, Denmark, on 1928 October 25, as the third child of an artist. While still in high school I developed an interest in astronomy, and with the guidance of the staff of the Copenhagen University Observatory worked on calculations of the orbits of comets and minor planets. I began my academic studies at Copenhagen University in 1947, getting my mag. scient. degree in astronomy in 1949.

The year 1950-51 I spent as a research student at King's College, Cambridge, England, working on the design of a program for the EDSAC for calculating the perturbed motions of minor planets. The years 1952-53 I spent in the USA, with visits to a number of astronomical observatories and computer development laboratories, followed by a second stay at Cambridge, England.

From 1953 to 1959 I was scientific assistant at Copenhagen Observatory, and also served as consultant in the areas of assembly language and debugging aids to the independent computer laboratory, Regnecentralen, on the development of the first Danish computer, DASK. I received my doctorate in astronomy in 1957.

In 1959 I joined the staff of Regnecentralen, specializing in the area of high level languages, and thus became heavily involved in the international development of ALGOL 60. I organized the ALGOL-Bulletin and became one of the thirteen members of the international team who produced the final design of ALGOL 60 in 1960, serving as editor of the team's report on the language, Report on the Algorithmic Language ALGOL 60.

As member of the compiler design group of Regnecentralen I contributed to the design of compilers for ALGOL 60 and COBOL, characteristic by their effective use of multipass techniques. This experience lead to an interest in the basic principles of data processing, resulting in a book, Concise Survey of Computer Methods, published in 1974.

Since 1969 I have been professor at the Copenhagen University Institute of Datalogy. In the more recent years I have been studying program development as a human activity, retaining a skeptical attitude towards the claims made for methods and formalizations in this field.

I have been co-editor of the Nordic journal BIT since its start in 1960. I served as president of Dansk Selskab for Datalogi from its founding in 1966 until 1982, and was co-editor of the report on the first conference on Software Engineering in 1968.

I have been married several times and am the father of four children. Jesper and Thorkil both work in computing, Birgitte is a singer and actress, while Barbara is still in school. Otherwise I am mostly concerned with classical music, playing and listening.

Awards: The G. A. Hagemann Medal in 1963, the Jens Rosenkjær Prize in 1966, the Computer Pioneer Award of the IEEE Computer Society in 1986.