  This presentation at the conference "50 years of CP violation", 10 - 11 July
2014, held at Queen Mary University of London covers an introduction to time
reversal and motion reversal, the phenomenology of K0-K0bar transitions,
unitarity relations, the first observation of T violation in 1970, later
results from Bell-Steinberger unitarity analyses, searches for T violation in
K0 to pi ell nu decay amplitudes and in the transverse muon polarisation of K
to pi mu nu decays, direct observation of T violation by motion reversal in
K0-K0bar transitions, and "direct T violation" in K0 to pi pi, I=2 decays
(epsilon-prime).
