He became interested in Mesmerism as a result of watching a demonstration by Lafontaine (1803-1892), whose personality and exhibitions were very similar to those of a Stage Hypnotist of the present day. Lafontaine came from a theatrical family, was very self-confident and would demonstrate the more dramatic Hypnotic phenomena on a particularly susceptible member of the audience or a "good" Subject he had brought with him. Braid's personality was quite opposite. He was calm, rational and well-balanced. After watching the demonstration in November 1841 he began to experiment for himself, and was soon demonstrating and lecturing and encouraging open discussion and criticism. He was attacked on both flanks. On the one hand the Mesmerists were naturally incensed at his undermining of the belief in some magnetic power they possessed. On the other there were the average men and women who were incredulous of the effects of Hypnosis and believed that some trickery was involved. Braid must have worked very hard, as must his publisher and printers, because his extensive book Neurypnology was published little more than two years after he first watched the demonstration.

His primary technique was to get the Subject to focus on a small bright object held very close (20cm - 40cm away from the eyes) in a position which strained the eyes and eyelids. This would generally lead to a spontaneous closing of the eyes, with a vibration of the eyelids. This response could be encouraged by moving two fingers of the right hand towards the eyes. The details appear in Braid's Induction.

He did not develop a detailed theory of Hypnotism other than to regard it as involving processes which could either depress or "prodigiously enhance" the activity of the nerves. He gave us the words "hypnotism", "hypnotise", "hypnotist", etc. He also used the concept of a hypnotic state, which is being avoided in this book.

Since Braid did not found a school, his influence waned after his death and the centre of Hypnosis moved to France in the second half of the nineteenth century. However, his book continued to be influential.