This book is 45 years old at this point, but it ages well. If you could ignore the handful of references to computers and floppy disks of the era, you could believe it was written relatively recently. We have, of course, learned since it was initially written, and the 30th anniversary edition I read did include some helpful interjections in addition to the extra chapters added to the second edition in 1989.

The Selfish Gene is and continues to be wildly popular for a reason. It provides an extremely accessible explanation of the mechanism of evolution, popularizing the concept that the gene is the fundamental building block that the whole process revolves around. What’s a gene? The definition he uses is approximately “any sequence of any length of DNA”, with the understanding that shorter sequences are more likely to survive longer unaltered than longer sequences, but allows him to ignore quibbling over terminology of specific lengths when it’s largely not meaningful to the concepts being presented.

The core idea is that genes that are successful are genes that increase the number of copies of themselves in existence. It explains the concept that there is a mechanism for even extreme “altruism”, such as an organism sacrificing itself for others to be selected for, if you recognize that multiple close kin relations each have many of their genes in common with that individual, and that dying saving several siblings increases the number of copies of your genes propagated to future generations than failing to do so.

It goes further into many other elements of how to view evolution from the perspective of individual genes, in specific environments, and how natural selection does and doesn’t work to change species over time.

One thing I’m not sure I was aware of, going into this reading of the book, is that Dawkins also coined the term “meme” and gave the first(?) presentation of ideas as replicators subject to very similar selection pressures as genes. This explanation is relatively simple and there are entire books on the concept now, but I did enjoy his short treatment here.