Since the invention of the dynamo and the technology of today, electrical machine has been found to be a very important tool in the operation of all equipment that requires electrical energy. They are found industrial setups, commercial and domestic environments. Electrical Machines are of various types: dc, ac and transformers. The book "Electrical Machines Book One" contains dc machines and transformers, the content of which is explicit enough for the understanding of anyone that picks it to study the theory of electrical machines. Each of the topic has an approach of good insight into the subject and the understanding of the fundamental factors common to dc machines and transformers respectively. The book basically contains most of the topics needed for the understanding of the theory, operation and maintenance of these machines. It also includes Questions Answers for practice and some worked examples to help the reader in his studies. The book will surely be of tremendous value to both the academics and professionals alike.