Ramana MaharshiWhatever thought may rise, not to let it live or grow, but to destroy it then and there, without the least slackness, by merging it back into its Source, is powerful and intense Vairagya [detachment].

Ramana Maharshi

Advaita Makaranda
Nectar of Non-Duality, by Lakshmidhara Kavi

Reference Materials:

Video/Audio Lectures

Swami Paramarthananda
7 classes (~90 mins each)

Swami Dayananda Saraswati
33 classes (variable lengths)

Advaita Makaranda - Class #1 - 1984 Spiritual Camp - Swami Dayananda

Swamini Satyavratananda
12 classes (~55 mins each)

Swami Viditatmananda
10 classes (search for "Advaita Makaranda" on the linked page)

Swami Tattvavidananda
7 classes (search for "Advaita_Makaranda" on the linked page)