Jnana Yoga seeks to uncover the truth about yourself and the universe through self-inquiry; its objective being liberation from limiting beliefs and attachments while realizing a shared divinity present within all beings.
Jnana is associated with Advaita Vedanta, a form of Hindu philosophy which draws heavily upon ancient scriptures (Vedas). This branch of yoga takes a nondual view of reality wherein Brahman (the ultimate reality) unifies with Atman (every individual being).
Adi Shankaracharya created Jnana Yoga to foster spiritual and emotional stability for his disciples, teaching renunciation as well as four core pillars of knowledge: hearing, manana or reflection and nididhyasana meditation. Also included are viveka or discernment and vairagya or dispassion/detachment which form what are known as its six virtues or virtues of Jnana yoga.
Practice of Jnana Yoga requires both intellect and spirit. For optimal results, practitioners should first engage in Hatha, Karma or Bhakti yoga in order to prepare themselves for its rigorous nature. Swami Sivananda provides an excellent outline of seven stages of Jnana Yoga that you may encounter as you pursue this path; intellectual understanding alone won't get them there; peace with oneself and others takes effort and dedication over time.