Martin Fowler has blogged about my Paper29 Jun 2004
Here are some interesting comments about our approach:
Much of my career has involved rewrites of critical systems. You would think such a thing as easy - just make the new one do what the old one did. Yet they are always much more complex than they seem, and overflowing with risk. The big cut-over date looms, the pressure is on. While new features (there are always new features) are liked, old stuff has to remain. Even old bugs often need to be added to the rewritten system.
An alternative route is to gradually create a new system around the edges of the old, letting it grow slowly over several years until the old system is strangled.
The most important reason to consider a strangler application over a cut-over rewrite is reduced risk. A strangler can give value steadily and the frequent releases allow you to monitor its progress more carefully.