In summary, "Programmable Logic Controllers: Principles and Applications" by John W. Webb appears to be a significant resource for both learners and professionals in the field of industrial automation. Its comprehensive coverage of PLC principles and applications makes it a relevant and useful textbook or reference book.
A major theme is the historical shift that occurred in the late 1960s, primarily driven by the automotive industry's need for flexibility. PLC Direct Replacement of Hardwiring
Programmable Logic Controllers - Principles and Applications