The subject of this book is the mechanics of Lorentz transformations which is commonly investigated under the title of special relativity theory. The motive for setting the subject of investigation as Lorentz transformations instead of special relativity is objectivity. However, we also investigate special relativity thoroughly as a possible interpretation of the mechanics of Lorentz transformations. The book originates from a collection of personal notes and tutorials about topics and applications related to modern physics and tensor calculus. The book includes many solved problems as well as extensive sets of exercises whose solutions are available in another book. The book also contains a number of high quality graphic illustrations. A rather thorough index is also added to the book to enable keyword search and provide a useful list for the main technical terms of this subject. Cross referencing is used extensively where these cross references are hyperlinked in the digital versions. The book can be used as a guiding text or as a reference for a first course on the mechanics of Lorentz transformations or as part of a course on modern physics or tensor calculus or even special relativity.