ENA book „Science of Science" is a last book in series of books, written by an author of this book, after her previous books „ A theory and Methodology of Informatics (Scientific information) (1985); „Methodology of Informatics" (1990); „Development of theoretical thought of Science of Science in the Lithuaniai in 1969-1989" (with co-author Ina Dagytė); „Development of a theory of informatics in the Lithuania in 1957-1990" (1996); „Bibliometrics" (1999); „Famous schools of Lithuanian scientists" (2002, with coauthors); „Famous Lithuanian Scientists of the XX-th Century" (2009). „Science of Science" is a book, in which is given theoretical generalisation of previous experimental and theoretical researches, which were described or not included in the previous books. An author of this book was working in the field of scientific information since 1966 and was engaged in scientific researches since 1973 (the first her scientific articles). A book „Science of Science" deals with researches of science in the West and the East (former the Soviet Union and its satelites socialistic states in the Europe) since the first book on „Science of Science", written by Alphonse de Candolle (Histoire des sciences et des savants depuis deux siecles - Geneve-Bale-Lyone, 1873) till 2000. In a book is given a new point of view to Science of Science, which proclaims, that every branch of science must have its theory, its history, its methology and its practise (industrial or teaching). Every of those parts of „Science of Science" is analysed in the book. There is a rich history of development of Science of Science in the West and in the East. In a chapter of theory are given main conceipts of Science of Science; are revealed relations among them.a new structure of this branch of science is given, contrary to that, which is used in Science of Science in the East and in the West, also are revealed different main objects of investigations of Science of Science in the East and in the West. A main attention is paid in the book to development of Science of Science in the Lithuania in the period 1969-2000; to achievments in a theory, metodology, history and practise of Science of Science. A history of this development is written. An author of this book is experenced researcher in the methodology of science, especially in the bibliometrics and scientometrics. She was the first in the Soviet Union, who published first articles on a theory of bibliometrics and wrote the first book in the East „Bibliometrics" (1999) Those her works have got a wide recognition (more than 300 citations) in the East and the West.