Why do Evangelicals like a spirituality book by a 16th century Catholic monk? I recall in my early days as a Christian I remember reading a book called ‘The Practice of the Presence of God’ by a Monk called Brother Lawrence in France.  It always baffles me a bit that this book exists at that time and that reformed theologians and evangelicals will recommend it to others.

Some think Protestants admire Mother Teresa, but I would have to say I have rarely seen a book by Mother Teresa in an Evangelical Christian bookstore but have commonly found this little book by Brother Lawrence?

What I am wondering is according to evangelical or reformed thought why would this book above possibly all other Catholic books in the last 1000 years be so appealing? Why would it seem so non-Catholic and acceptable to those who strongly oppose Catholicism?
The Practice of the Presence of God is one of a variety of different Christian "classics" which really cross denominational boundaries (Imitation of Christ might be another). Since the truths it discusses are universal to Christianity and because there is very little in the document which must be Catholic, its benefits are generally considered to far outweigh the detriments. 

But, here is a counter question: if it is acceptable to read documents by other Protestant traditions/denominations, why is it unacceptable to read Catholic material as well? From the perspective of a devout Calvinist, Bonhoeffer got some things dead wrong, but he was recommended reading in my Presbyterian Church. C. S. Lewis is an Anglican, but you'll often see Baptists reading Mere Christianity. Chesterton is a Catholic, but Orthodoxy is one of the better apologetics texts in the English language. If all of these alternate theologians are acceptable, why is it unacceptable to read the writings of a humble monk on how to live one's life?