Nexus: Small Worlds and the Groundbreaking Science of Networks

Nexus is a truly remarkable book. It is a popular science attempt to present and explain one of the most remarkable scientific discoveries of the last century: modern network theory. It focuses especially on two classical theories, the Small World Phenomenon and the Strength of Weak Ties, and elaborates and enlarges on them with some recent mathematical discoveries. Despite the fact that much of the recent developments are heavily mathematized the book remains faithful to its popular scientific approach. Thus it deliveres what it promises.Mark Buchanan manages to keep the delicate balance between intuitive understanding and rigorous analysis; a balance that most popular science books I have read fail to keep. Thus it offers both an intruiging and stimulating read as well as a truly convincing and enlightening scientific argument (beat that you postmodern pseudoscientists!) Another mark of its excellence is that while doing its declared tast it simultaneously treats the reader a veritable tour de force of the collected scientific wisdom of the modern world. In that it reminds of another excellent recent book, namely The Da Vinci Code by Dan Brown. Both books thus have plenty of added value and are a feast for the senses as well as the mind.At the same time the book manages to infuse the reader with a sense of optimism about the future of science and humankind; an important accomplishment given the many attacks that science has received lately by many pessimistic and nihilistic postmodernists. This fact also makes the book the more enjoyable; few people really want to read pessimistic monologues. In conclusion: everybody with an interest in social or physical networks should read it. This is a theory of tremendous explanatory power. A prime nobel prize candidate.

In this book, I think Buchanan makes a fairly convincing case that the natural, human, and technological worlds naturally tend to organize themselves into networks consisting of (a) clusters of strongly connected elements and (b) a relatively small number of weak links which fairly randomly connect the clusters. Such networks are "small worlds" because the shortest path from any element to any other is usually quite short, typically on the order of six steps or less, even for networks as large as the entire global human population of 6 billion people.When all the elements in a small-world network have a comparable number of links, they are called "egalitarian," but some "aristocratic" small-world networks also have hub elements which are more highly linked (according to a power law or "fat tail" relationship). Either way, small-world networks tend to be efficient and robust, although they are also vulnerable to disfunction or complete collapse if a significant percentage of their weak links or hub elements are lost.The above summarizes the basic concept, which Buchanan fleshes out with many examples spanning many fields (biology, economics, physics, epidemiology, information technology, business, politics, etc.), and he also adds a human-interest element by telling us about specific researchers and their working relationships. Buchanan is a top-notch science writer, and so he relays all of this in an effective and entertaining manner.The only downside is that the book format gives it more of the feel of a novel rather than a textbook, so key points are not highlighted and it's difficult to go back and find information. I think this is a significant downside because it hinders the serious reader who wants to use the book as a reference and explore the topic further, so I'm giving the book a four-star rating instead of five. However, I still highly recommend the book to readers who are interested in general popular science, and especially network theory. This topic has an important place in the broader and increasingly important subject of complexity theory.

I heard of Mr. Buchanan's work from a radio here and I borrowed it finally from the library of the university I studied in. Frankly, I could not put it down once I have read the first 5 pages.Just like what the author suggests in the book, the study of world phenomenon under the context of physics is still at its new-born stage. Please do not expect too high. But that would never reduce the meaning of such academic field to our world. It opens our eyes by leading us to a drastically different perspective with which human beings can view the world.For instance, if later and further experiments and studies prove that the distribution of wealth must be the way it is now (i.e. much wealth in hands of a small group) since it is one of the laws followed by the world, then the arguments of left and right will become totally meaningless. The main question for human beings will then be how should all of us live our lives, given whatever position we are situated along the scale of wealthiness.Also, one should not forget that, as warned by the author, that the concentration of wealth will get worse and irrevertible when the system fails to regulate the misuse of power brought by the accumulated wealth so that it passes the tipping point. This is the most impressive revelation that I had found in the book.The book is so good that I have just got one from Amazon to fill my collection.

This is new and exciting stuff. It draws together work by Strogatz and others who have contributed parts of the narrative that is now so ably set out in this text. The capacity of network models to explain apparently disordered behaviour in populations so various is vastly stimulating. It's better than fine dining and sex.

The beginning of the is excellent. Nice introduction to network and graph theory and the similarities between different areas. However, the second half feels more like an attempt to convince the reader that world social and ecological problems can be explained and solved with network improvements.