Hi, Patsy --

Fr. de Mello (may he rest in peace) is an easy case: Cardinal Ratzinger's [now Pope Benedict XVI] department (the Congregation for the Doctrine of the Faith) published an official warning about a year ago about doctrinal ambiguities in de Mello's writings. You can find the text of the statement on the Catholic Culture web site.

Meister Eckhart is described in the Catholic Encyclopedia article online. According to that article, he wrote in an un-technical way which made his writings prone to misunderstanding, but often corrected the misleading parts latter on in the same sermon or treatise.

When accused in 1327 of teaching dangerous doctrine, Eckhart admitted that some of his statements could be taken in an unorthodox manner. He explicitly rejected those unorthodox ideas and submitted himself to the Pope. In 1329, Pope John XXII condemned 17 statements from Eckhart's writings as heretical, and some other statements as suspected of heresy.

Thomas Merton's writings are a mixed lot: you'd be safe reading his early books such as _The Seven Storey Mountain_ or _The Sign of Jonas_. Catholic Culture has a helpful article about Merton.

Of course, there are many other Catholic spiritual writers. You could take a look at St Francis de Sales ("Doctor of the Church" who focused on holiness for lay people) or St Teresa of Avila (also a "Doctor of the Church" pre-eminent for her spiritual teaching). Among 20th-century Catholics, there are excellent works by such writers as, for example, Catherine de Hueck Doherty, the Russian-born Catholic who founded the "Madonna House" lay community.

I hope this all helps!

Thanks for writing--

Richard Chonak