The International Library of Technology Series of books was published by the International Textbook Company of Scranton, PA at the beginning of the 20th century. The series covered technologies current to 1900, and it also included books on electric and steam train technology. The two books of this series in my collection include: ELECTRIC RAILWAYS and ELECTRIC RAILWAYS: EFFICIENCY TESTS and CONVERTERS, 1905 and 1908 respectively. From the historical perspective of early train technology this series is fun to study, but some understanding of the topic is helpful, they maybe old, but they are highly technical with numerous engravings to support the text. If you volunteer at a trolley museum you will find these books helpful and likewise steam. This is an overlooked series of books that are very reasonably priced, but they are priceless for their historical perspective. Highly recommended.