Bhagavad-Gita was originally spoken to liberate one from the bodily conception of life, and Arjuna put himself in this position in order to receive this information from the Lord. One must become free from the bodily conception of life; that is the preliminary activity for the transcendentalist. One who wants to become free, who wants to become liberated, must first of all learn that he is not this material body. Mukti, or liberation means freedom from material consciousness.
The book is a introductory part of Prabhupada's book Bhagavadgita as it is. The book clearly explains the subject matter of Bhagavad-gita (BG), the purpose of BG, the spirit of approach to BG, the process of understanding BG and the result of understanding BG. The book's main observation is that BG itself mentiones that BG is approached in a devotional mood to understand its message. The message is hidden for one without devotion.
The purpose of BG is to make man understand the cause of suffering and method of release from suffering. One should appreciate how Arjuna accepted Krishna as Supreme Personality of Godhead. The verses of chapter 10 are drawn attention. The subject matter of BG is five: ISVARA (God), JIVA ( Living Entity), PRAKRTI ( Material Nature), KALA (Time) and KARMA ( Activity). The process of understanding involves in accepting Gita as Scripture. The essence of understanding BG is to surrender to God and act according to His will. One's life is purified and he returns to the Kingdom of God. The Supreme Lord is transcendental and eternal. Jiva is also eternal and spiritual. BG reawakens Jiva to this relation. The Svarupa of JIVA is Krishna-das ( Servant to God). True happiness for Jiva is serving God. One should worship only the Supreme not the demigods. One who thinks of Krishna at the time of death goes back to Krishna' s abode. By studying Vedic literature, one's thinking can be purified. One should practice Krishna-consciousness all the twenty four hours. There are nine processes of devotional services ( Listening to Krishna-Katha, Singing His glory, Remembering His Glory...). The process should be learnt from an authority (Guru in parampara).