Staff selection by scientific methods is discussed, and reference is made to the designing of tests and to the means of proving their usefulness. The use of statistical methods is considered. A number of tests are described and samples are given.The application of the above principles to the staff selection problems in a light electrical engineering factory is described. The procedure for staffing a new department is detailed and reference is made to the other classes of labour which are dealt with. A note on the selection of engineer apprentices is included.The last section of the paper deals with the technique of the interview.In the Conclusion the authors mention the origin and growth of their work as indicative of its usefulness, and refer to co-operation between various departments in the factory which are concerned with personnel.