Don Mackean's biology textbook was first published in 1962. Today, it is still being used in schools all over the world, from Portsmouth to Port Moresby in Papua New Guinea.
Donald Mackean was born in November 1926 and raised in Hastings. As a boy, he loved nature and, specifically, bird-watching. He also enjoyed drawing: he would illustrate cards for family and friends with pictures of Mickey Mouse.
He went on to win a scholarship to study natural sciences at Clare College, Cambridge. It was while at Cambridge that he met Margaret Cornes, a trainee teacher. The two married in 1948 and had two children, Ian and Sally.
Mr Mackean's first job was as a science teacher at Dauntsey's School in Wiltshire. In 1952, he was appointed head of science at Sherrardswood School in Hertfordshire. Frustrated with the available biology textbooks, he began to create his own worksheets, with drawings meticulously copied from nature. One pupil's father was so impressed that he contacted publishers John Murray, which asked Mr Mackean to compile his work into an O-level textbook. In 1962, Introduction to Biology was published. Eventually, it would sell millions of copies.
In 1965, Mr Mackean embarked on a data collection tour of Nigeria and Ghana to produce a tropical edition of the book. With characteristic perfectionism, he attempted to find every plant mentioned in the book so he could draw them from life.
He left the classroom in 1970 and began a series of lecture tours, many in Africa. Equipment in the schools he visited was very basic, so he travelled with a large suitcase, specially adapted to hold his many specimen jars. And he used his royalties to endow a scholarship scheme in Britain, giving science teachers time out of the classroom to develop resources.
Mr Mackean's textbook, now called GCSE Biology, continues to sell. Last year, the Australian government donated thousands of copies as aid to Papua New Guinea.
Don Mackean died of heart problems on 30 January.