Yesterday I read a book called 'A simple way to pray' by Martin Luther. I read it on the basis of a review by R C Sproul, author of the classic work 'The Holiness of God' (on my essential reads list).
A simple way to pray was written for Luther's barber to help him pray and is only 34 pages long. In this edition, there is an excellent chapter on the spiritual disciplines at the end of the book. For more on the disciplines do make time to read Don Whitney's 'The Spiritual Disciplines of the Christian Life'.
Here's the review:
"No book has done more to revolutionise my personal prayer life than this little book by Martin Luther"