[2] After live video record of the experiment with Niko Tinbergen, Sewall Wright called the study as "the clearest case in which a conspicuous evolutionary process has actually been observed.

During 1929 he began clinical training at St Bartholomew's Hospital, London, then during 1935 joined a general medical practice in Cranleigh, Surrey.

Kettlewell's research from three surveys between 1952 and 1972 seemed to show a static pattern with a high frequency of the dark-coloured carbonaria phenotype in industrial regions, and the light coloured typica moths the most common in more rural areas.

[6] He demonstrated experimentally the efficiency of natural selection as an evolutionary force: light-coloured moths are more conspicuous than dark-coloured ones in industrial areas, where the vegetation is darkened by pollution, and are therefore easier prey for birds, but are less conspicuous in unpolluted rural areas, where the vegetation is lighter in colour, and therefore survive predation better.

He reported that during 1965–1969 he attempted to perform similar experiment, and found that birds did not have preference on moth on either black or white tree trunks.

She accuses Ford of being a Darwinian zealot who exploited Kettlewell's servitude[16] and criticises scientists in general for credulous and biased acceptance of evolution.

[17] A review in EMBO Reports describes the book as "Hooper's exhilarating account of the public and private lives of an opinionated and powerful group of evolutionists, who contributed to this shameful episode in the study of evolution.

[25] Because of vigorous field research, Kettlewell suffered from bronchitis, pneumonia, pleurisy and flu, along with heart problems.