My main interest has been in the study of weak interactions, and, in particular, decays of "strange," "charm" and "bottom" quarks. The weak force is responsible for these decays; analogous decays of the "down" quark underlie the radioactive decays of elements. Four out of seventeen fundamental parameters in the standard model of strong and electroweak interactions (SM) are called "Mixing Angles", and determine the rate of decays of quarks. The decay of the bottom quark sensitively depends on two of these. There is great interest in understanding the decays of bottom quarks because the determination of two fundamental parameters is at stake.