This question is not properly answered presently. Only after reading the "Ceylon to Almora lectures" of Swami. Vevekananda I understood that for centuries Hinduism is based on three concrete faiths. I have contemplated and wanted to understand the development of these faiths. Therefore, I have read many books related to Hinduism. Later in my age the books of the Siddhas, the ancient learned men of South India gave me some obvious understanding of the subject.
This understanding gave me some clear ideas regarding the subject "Hinduism".
First, it gave me an understanding that Hinduism is not a religion, but a philosophy of life.
Unlike other philosophies of life, it is founded on three systematically enumerated faiths. The way of life adhering to this philosophy of life is Hinduism. It is a process of development of the inner spirit or soul of man. So, it is called Spiritualism. The book reiterates that only those who believe in these three faiths can only be called as a Hindu.
This book chronologies the three faiths of the Hindu and establishes them with the help of the learned men of this land India. This is also done systematically. In doing this it, systematically discusses various philosophical points related to these faiths. This is done intentionally because Hinduism contemplates the internal spiritual world of existence and not the external material world of existence. This book enumerates the ultimate spiritual goal, the methods leading to it and calls it as Spiritualism.
Therefore, as this Book is a systematic analysis of this Spiritual advancement or Spiritualism, it is given another name that is "A manifesto of Systematic Spiritualism"