Short works

Books : reviews

Steven H. Strogatz.
Nonlinear Dynamics and Chaos: with applications to physics, biology, chemistry, and engineering.
Westview Press. 1994

Steven H. Strogatz.
Sync: rhythms of nature, rhythms of ourselves.
Allen Lane. 2003

rating : 3 : worth reading
review : 6 June 2004

This is a very nice book, for a number of reasons. Strogatz wants to explain the science behind "sync" -- synchronisation and emergent order from large numbers of simple non-linear systems. He covers a wide range of phenomena, from fireflies flashing in sync, our circadian sleep cycles, synchronised applause in concerts, lasers, the London Millennium Bridge wobble, fibrillation and heart attacks, brain waves and epileptic seizures, and much more, illuminating the underlying behaviours and exposing their similarities.

He also wants to give a feel for the excitement of doing science. He does this by interleaving his story with little vignettes of the actual scientists involved, and how they go about their work, including some personal anecdotes, bringing the process of science to life. He structures the story logically, rather than historically, so we find ourselves jumping around the decades. I find this structure works well: we get to understand the science in a coherent manner, whilst getting a feel for how the progression of understanding is not in fact linear.

Along the way Strogatz also manages to illuminate a particularly crucial technique necessary for doing a certain kind of science: that of modelling, of taking a messy, complicated system, abstracting out the crucial features and examining them, whilst maintaining an awareness of what has been left out and what assumptions are being made. Take a firefly, and pare down its behaviour to a simple increasing potential with a threshold. Add in a spatial component to get locality and travelling waves. And so on. All this is accompanied by little discussions of how seemingly small changes in the modelling assumptions (for example, changes in the distribution of timings) can have large effects on the tractability, and on the actual results.

One particular simplifying assumption is the connectedness of the components: usually either all connected to all, or each connected only to its nearest neighbours in a regular pattern, neither of which is a particularly good approximation to reality in many cases. Strogatz and his then student Duncan Watts are most recently famous for their Small Worlds work (also described in Buchanan's Small World), an intermediate kind of connectedness. We get a chapter on that work, not just slapped on the end, but described in the context of making a more realistic model of the connectivity of sync.

All this is written in a very readable style, providing a lot of information and understanding on a range of levels. So, worth reading for all these reasons.