Great books on the teachings on prayer by Sts. Teresa of Avila and St. John of the Cross:
"Prayer Primer" by Fr. Thomas Dubay (amazon.ca link)
"Fire Within" by Fr. Thomas Dubay (amazon.ca link)
"Prayer Primer" by Fr. Thomas Dubay (amazon.ca link)
"Fire Within" by Fr. Thomas Dubay (amazon.ca link)