In this talk I will discuss the 30-year search that culminated in the conclusion that then energy spectrum of electrons emitted in β decay was continuous. This posed a severe problem because if, as most physicists at the time believed, β decay was a two body process, then the conservation of energy and momentum required that the electron have a unique energy. Wolfgang Pauli proposed a “desperate way out” of the problem: in β decay a third, light, neutral particle was also emitted. In such a decay, the electron was not required to have a unique energy. The conservation laws were saved. I will also discuss some of the subsequent history, culminating in the observation of the neutrino by Reines and Cowan. This history will not be one of unbroken progress and success. It will contain missed opportunities, errors, false starts, and dead ends. It will also include instrumental artifacts, misinterpreted and incorrect experimental results, and incorrect theoretical assumptions and calculations. In short, it will show that science is a fallible, human enterprise, but one that does, in fact, produce knowledge of the natural world.