This is an excellent book for someone responsible for OJT directly or even indirectly, ex. a Human Resources Manager. Dr. Rothwell provides a very clear and easy to follow format for establishing or fixing a broken OJT system.
I'm an HR Manager, and I used Dr. Rothwell's book as a part of a training program for our employee trainers who train our new and existing employees. They would read material assigned from the book and then make application to problems we experienced in our training. Using a facilitative style of training, in addition to the book for follow-up, provided for a good transfer of learning.
I highly recommend this for someone willing to put the effort into implementing or repairing an existing OJT process.