Catholic
Lorenzo Scupoli’s classic book on spiritual combat: distrust of self, trust in God, and steady warfare with the passions.
Kindle edition — on Amazon
Kindle edition sold by Amazon. This edition is for readers who want the work itself, not a summary.
Text from the 1875 Rivingtons English of Scupoli’s Spiritual Combat — Chapters I–LXVI, the Combat proper. The translator is anonymous on the title page.
Prepared for deep reading: spelling and punctuation are lightly modernized; ascetical vocabulary and the archaic second person remain. Chapter arguments appear beneath titles as short extracts.
Elsewhere, free PDFs give you the words. This edition is designed so you can stay with the argument — and you keep the book.
Three companion volumes on the same question: How does the believer put sin to death?