Abstract
Tracking systems in particle physics have evolved over many decades,
including nuclear emulsions, bubble chambers, spark chambers, drift
chambers and silicon microstrip detectors. Over the past 30 years,
silicon pixel detectors have carved out a small but important niche as
vertex detectors. Recent advances in the very simplest of this family
(monolithic devices) suggest that they may be ready to assume an expanded
role for large tracking systems (~100 m^2) in some classes of experiments.
The key developments leading to this potential revolution will be
explained, particularly for the benefit of non-experts in the subject.