He covers the history of CGM at Dexcom from the very beginning. It is interesting that they originally were researching an implanted sensor that would last a year, but decided it was not practical. They then began developing the current type of if patch sensors.
As someone who worked in electronic product research and development I imagined the brain storming sessions that were and still are happening at Dexcom. One of my favorite parts was the use of a Motorola pager case for the 1st receiver.
This is fairly long but it is well worth the time.