Training Within Industry was a programme devised by the United States Department of War beginning in 1940 when it came to realise that a lot of people who worked in factories making materials needed for the Second World War were being conscripted into the armed services.

This meant that the very companies that the Department of War was placing orders with on a greatly increasing scale didn’t have enough staff to produce them. The people they had trained for years and had the skills required were no longer there, so the only way to replace them quickly enough and reduce the shortfall would be by improving the methods of job training.

A large number of experimental training methods were produced by a team of experts loaned by private industries, but many of them were discarded, eventually producing a set of four ten-hour training sessions called Job Instruction, Job Methods, Job Relations, and Program Development. Each of these training sessions had introductory sessions called "Appreciation Sessions" which were used to "sell" the idea of the programmes to senior management and also introduce them to the middle management of a company.

In order to introduce the programmes to a business, the TWI trainers had to be invited to the factory by the company’s directors. So that they could sell the idea to the company, the trainers developed what they called The Five Needs Of The Supervisor which were Knowledge of the Work, Knowledge of Responsibility, Skill in Instruction, Skill in Improving Methods, and Skill in Leading.

The ten-hour training sessions began with Job Instruction. This programme taught managers and supervisors a way to train new recruits faster. It showed managers and supervisors how to break down a job process into small steps, showing the necessary procedures and explaining the key points, while also explaining the reasons for the key points. When this had been done, the new recruit would be allowed to attempt the work under close supervision and coaching. Then the coaching and supervision would gradually be reduced until the recruit was able to manage without further coaching. The trainers devised a slogan "If the worker hasn’t learned, the instructor hasn’t taught". The Job Instruction courses certainly gained a following, and at the request of industries other than manufacturing, variations to the Job Instruction courses were developed for farming, hospitals, and office workers.

The second session was Job Methods which was a programme that taught workers how to evaluate the efficiency of their jobs and to methodically suggest how improvements could be made to the process. This broke the job down into motion steps with the workers taught to analyse each detail and consider whether or not there was a good reason to continue to do it the same way by asking themselves a series of pointed questions.

If they then decided that a particular detail could be done in a better manner by simplifying it, rearranging it, combining it with another detail, or even removing it altogether, they were then to "sell" the idea to their line manager and co-workers. This would then be assessed on grounds of safety, quality, quantity, and cost, and if approved would be introduced into the process as standard. The worker who produced the idea would be given due credit.

The next session was Job Relations, and this was a course which taught supervisors and managers how to deal with their team members in a fair and even-handed manner. It laid emphasis on the fact the "people must be treated as individuals."

The fourth session was Program Development, and this taught the supervisors and managers who were responsible for the training to assist the line organisation to solve production problems through training.

An additional programme was developed for use by the trainers called "Management Contact Manual" (1944) which was a formal training course on how to sell the TWI programs to management. "How to get Continuing Results from TWI Programs in a Plant" was also developed in 1944 and this training program was the result of two years of practical experimentation and experience on what it took to have a successful implementation of TWI.