Dr Aravind Nilkanth Navare (78) of Pune, Maharashtra has been writing a postcard to his son Ajit Aravind Navare in Mumbai every day about Chintan, a programme broadcast on All India Radio (Pune Centre) daily at 6.40 am. The first letter was written on March 30, 2001. Aravind has completed 5,200 letters to his son as of June 20, 2016. Ajit has kept all the letters, a perusal of which would be quite a good read, even today. Incidentally, this is the 13th time since 2005 that this record is mentioned in Limca Book of Records! Based on selected letters Aravind has now published book Chintan-Manthan in Marathi.