We cannot say enough about Light and Peace: Instructions for Devout Souls to Dispel Their Doubts and Allay Their Fears which was written by Father Carlo Guissepe Quadrupani (b. 1740- d. 1807).
Fr. Quadrupani was an Italian priest of the Clerics Regular of St. Paul (the Barnabites). He wrote this book based on the tender teachings of St. Francis de Sales, St. Augustine, and St. Philip Neri. The book is in the public domain so it may be downloaded for free on the internet, listened to (for free) on LibriVox, or purchased on Amazon for a modest fee.
Fr. Quadrupani must have had extensive experience in spiritual direction for he seems to possess a knack for, as the book title suggests, dispelling doubts and allaying fears, and leading souls to light and peace.