The title of this chapter suggests the answer and the theme. 

      The 'Uttama-Purush' means the top most person, God Supreme or the maker of this wonderful and perfect universe. HE is introducing Himself in first person singular as "I". A seeker of God has to know and unite (Yoga) with this Purushottama or Supreme self. 

    The last six chapters of the Gita are for intellectual seekers of God. It is a path of God realization by self-realization. A student has to seek an answer to a standard question, "Who am I?" by a path of Yoga meditation.

    Scholars of the Gita rank this 15th chapter as number one for understanding body, mind, intellect, material world, Supreme invisible God and spirituality. Combined with logic and reason, this chapter shows to any curious student a path of seeing one invisible and formless (Nirakar) God. The last verse (20) declares that this particular chapter is an extract of all sciences and self-knowledge. 

     There are only 20 verses in this chapter, which are easy to memorize. The verses are in nice Chandas. They are chanted in many Indian musical 'Ragas' like Yaman-Kalyan, Bageshri or a melodious Raga like Bhairavi. 

     This chapter is usually chanted at the time of final death rituals, by the side of dead body, when the relatives are offering last respects to departed soul with flowers and garlands. A student of the Gita has to memorize these verses and repeatedly chant them for days and months. 

     When I was nine years old I had crammed this chapter of the Gita. I did not understand any meaning of the verses. But I was singing this chapter as a Sanskrit prayer, years prior to learning Sanskrit as a second language in my high school. Even after learning some Sanskrit, I did not understand the meaning of Purushottama. At my age of sixty, I translated this 15th chapter in Gujarati in 1988 and published a booklet. Again at my age of seventy- four, I translated it in English. 

    This teaches two important lessons. (1). The understanding of the meanings of verses is not necessary to memorize poetry in any language. (2) It takes years before the deeper meaning of scriptural verses become clear to mind and one can explain it to others in a different language. 

     The word 'Purusha' has many meanings in Indian scriptures. Purush = a man; Stri = a woman. Its literal word meaning is a man or a male. In a general sense, Purush means any human being (male or female) One living individual (Vyakti). Purushottama = Purush + Uttama. Uttama means Supreme. God is only the top most Supreme Purusha. By understanding, searching and uniting with Supreme Being (Purushottama) an individual becomes God like. 

        Many Indian Gurus and scholars understand and explain the word Purush as Soul, Spirit or Atma. In his Sankhya Darshana, Kapil refers to a 'Mahat Tatva', in the sense of soul or Purusha. 'Mahat Tatva' means the top most element (Imperishable Soul or spirit). 

             According to Kapil, there are only two things in this Universe. Prakruti and Purusha. According to some Gurus 'Mahat Tatva' means Soul, and according to others it means Buddhi, the highest purified intellect within us. The 'Nir-Ishvar Sankhya' of Kapil (Atheist Sankhya Philosophy) does not believe in one God. There is a modified version of Sankhya, Se-ishver Sankhya, which believes that the maker of Prakruti (Mother Nature) is a real Purusha or GOD. 

       The 13th and 14th chapters of the Gita discuss Purusha and Prakruti in great details. According to some Gurus both, the soul and God Supreme are one. But according to this 15th chapter there are three different basic elements. 

     A short and correct answer to above confusing discussion is seen in this chapter's verses Nos., 16 and 17: - Dwavimau Purushou loke Ksharaha ch Akshara av ch Ksharaha sarvani Bhutani Kuttastha Akshara Uchyate (V-16) Uttama Purusha tu anya, Parmatam eti Udahrutaha Yo lok-trayam avishya Bibharti avayam Ishvaraha. (V-17) The first line says there are two Purusha, one is Kshara (Perishable), gross material body made-up of the five basic elements of mother nature, and second one is Akshara (Imperishable) which is the Cosmic Atomic Energy hidden within gross body.