One of the spiritual classics of the last one hundred and fifty years is the book ‘Soul of the Apostolate’ by Dom Chatard. In it he writes of the spiritual life with detail, clarity, and relevance. This book inspired many throughout the years and a Catholic Conference recently featured lectures on its themes. Many of those talks by noted churchmen and theologians are available through its website:
https://www.souloftheapostolate.com/