The scientific manuscripts left unpublished by Ettore Majorana: with outlines of his work

In the Introduction to the Book, we present a panoramic view of the main scientific manuscripts left unpublished by the brightest Italian theretical physicist of the XX century, Ettore Majorana. We start recalling: (i) his very original ``study" notes (the so-called Volumetti), already published by us in English, in 2003, c/o Kluwer Acad. Press, Dordrecht & Boston, and in the original Italian language, in 2006, c/o Zanichelli pub., Bologna, Italy; and then present: (ii) a selection of his research notes (the so-called Quaderni, written by Majorana between 1927 and 1933), published for the first time in this book by Springer, Berlin. We seize the present opportunity for setting forth also some suitable ---scarsely known--- information about Majorana's work and life, on the basis of documents (letters, testimonies, different documents...) discovered or collected by this author during the last decades. In the Section "This volume: Majorana's research notes"of the present Introduction [pages XXIX - XXXIII f the Book] we call the reader's attention to some of the most original problems expounded by Majorana, often employing group-theoretical arguments (and applied by him to atomic, molecular, and nuclear physics). For instance, Majorana, before 1933, wrote down Dirac-like equations for spin 1, 3/2, 2, etc., discovering the method --later on published by Pauli and Fiertz-- for writing down a relativistic quantum equation for any spin. He investigated in a personal way, with new results sometimes not yet known, topics ranging from electron scattering to suitable superpositions of Dirac and Maxwell fields (yielding e.g. an explicit expression for the angular momentum carried by a real Dirac field).