Although the title of this book contains the word ‘unwelcome’, this book is the most welcome addition to the biological literature. Written by a clinical parasitologist, it provides very broad perspective on how we co-evolved with a variety of other organisms, how we cope with a number of parasites now and how we should deal with them in the future.

On the personal level, reading the chapters describing well known helminths and their life cycles brought back memories of me sitting in the first-year course of zoology being a fresh student of biology. Basic facts, still fascinating, have not changed in the last 40 years, I found. Reading on, I became enthralled by the richness of knowledge regarding a vast array of parasites, their complex interactions with us, with the natural environment and with national and international bureaucracies that try to devise the ways to control parasitic diseases. Heroic efforts of health workers resulting in major improvements have gone largely unnoticed as they are not ‘breakthroughs’ based on the feats of molecular biology, but patient and laborious public health efforts, saving often many more lives than highly publicised cures for specific cancers.

The basic message of the book – that we are a part of the very complex ecosystem – leads to the conclusion that killing other organisms, even if immediately harmful to us, may not be a practical solution. In the author's own words: ‘… we should proceed with caution. In many instances, a compromise may be necessary – a level of cultural and emotional tolerance, a manageable balance between devastating disease on one hand and species extinction on the other.’

At a practical level, last semester I was running, for the first time, the course on evolutionary medicine. The book gave me ideas, and material, for some lectures that were very well received by the students.