In 1986, on the 500th anniversary of the advent of Sri Caitanya Mahaprabhu, Srila Gurudeva composed an article in Bengali, entitled "The Speciality of the Gift of Sri Caitanya Mahaprabhu." That article has now been translated into English and made into a small booklet, presented by the Rays of The Harmonist team. It is available in Navadvipa at Sri Sri Kesavaji Gaudiya Math, now at the time of parikrama.
An excerpt from the booklet is as follows:
"Sriman Mahaprabhu gave full freedom to His unprecedented mercy (karuna) potency, telling her, 'Karuna, I surrender unto you. In whichever direction you choose, however far you want to go, and to whatever place you want to travel, drown everyone – the offenders, the antagonists, the neutral, the faithful, the faithless, the ordinary devotees and the special devotees – in the flood of prema.' "
Also another title just posted, The Principle of Sri Guru and Service to Sri Guru is available for download here.