Hanumanchalisa was written by Goswami Tulsidas in sixteenth century. Goswami Tulsidas also authored the epic Ramcharitmanas. Tulsidas used to recite ramcharitmanas for public. One day he happened to meet Lord Hanuman during one of his ram katha public delivery. Lord Hanuman then helped Tulsidas meet Lord Rama and Laxman. Lord Hanuman also helped Tulsidas several times during his life span. Hanumanchalisa was written by Tulsidas for showing gratitude and in praise of Lord Hanuman.
It is believed that reciting Hanumanchalisa helps one get out of all the fears. Even keeping Hanumanchalisa with oneself helps him get rid of all problems of life.