Why is it easier to find out what experience shoppers worldwide have had with the latest digital camera than it is to determine what adverse events patients have had with a particular drug? Why are blood tests and X-rays repeated needlessly? Why can one replace an application on an iPhone with a mouse click and require a team of engineers to do it for an electronic health record system? Mirroring the systems approach taken in biology, we have attempted to answer (through design and implementation) these questions including the pioneering of personal health record systems, distributed clinical query systems, and privacy protection mechanisms and policies. Most recently, we have focused on how to re-engineer electronic health record systems so that they are as easy to manage and customize as other complex but consumer facing systems (e.g. the iPhone) which fundamentally support our notion of substitutability.