About the series: The Human Upgrade

Using their ideas and their billions, the visionaries who created Silicon Valley's biggest technology firms are trying to transform the most complicated system in existence: the human body.

Previous articles in this Washington Post series looked at tech titans seeking ways to prolong life and the self-quantifying movement (QUANTIFY, moved May 9) and future installments will include a story on efforts to understand the brain through data and artificial intelligence. The series also will include Q&A interviews with tech titans such as Peter Thiel, Bill and Melinda Gates and Vinod Khosla (moved May 9).

Part one, about tech titans' seeking ways to prolong life, is viewable here: http://www.washingtonpost.com/sf/national/2015/04/04/tech-titans-latest-project-defy-death/