The idea for this book emerged in the late 1980s when I attempted to find an interesting Darwin quote to add to a volume I was then editing on the impact of El Niño on Peruvian fishes and fisheries. I remembered from earlier readings that Darwin had been in Peru, where he collected specimens of the species which Leonard Jenyns later described as Engraulis ringens, the Peruvian anchoveta.

But I did not find any suitable quote: the indexes of books by, or about, Darwin that I consulted all covered ‘finches’ but not ‘fishes’. Still, the pun was obvious, and I decided to write a short essay on Darwin's work on fishes, to be titled Darwin's Fishes, if only to get it out of my system.

However, caught in the iron grip of the Law of Unintended Consequences, I ended up writing a book-size chrestomathy. Fortunately, I had the help of Darwin (who contributed about 45 000 of his words, i.e. almost one third of the entire book) and, as we shall see, the help of friends who provided relevant information and helped verify facts.

The book now completed, I will attempt to cover my tracks, and pretend that this was written to fill the ‘major gap in scholarship’ that is usually recruited in such cases.