The very best books on the Saints are those written by the Saints. Not to say this is true in every instance, but rather as a general principle. Now these lives of the Saints by the Saints can be easily broken down into two main categories: First are Autobiographies of Saints and the second Biographies of Saints written by Saints.
Of the latter the best and most accurate as well as spiritual lives of the Saints are to be contained. They are almost always short and to the point and leave out all the extra fluff, conjecture, and bad commentary (if there is commentary they actually know what they are talking about and it is very good). Also, in many cases, these lives were being written by the Saints who knew the Saints they were writing about personally or at least lived in close proximity to the time when the Saint they were writing about lived.
Of the former it must be said that these books are a totally different sort of life of the Saint. In some cases there is much more of their spiritual journey and much less of their lives, and often only the particular events of their life that impacted their spiritual journey are mentioned. This has led some into confusion about certain Saints because they think they are getting a life story of a particular Saint in their autobiography, and in fact they are not. Not to say these sort of autobiographies are not wonderful, because they are, but they simply are not going to give you the whole picture.
The work that falls into this category most often today is the autobiography of Saint Therese of the Child Jesus and of the Holy Face: Story of a Soul. It is a wonderful book, but if you only read Story of a Soul you simply do not know Saint Therese. It is essential that one read her official biography: Story of a Life, and other books like My Sister Saint Therese, (by here sister Celine), the interviews during the process of her beatification and canonization, and the notes of her sister Pauline (Mother Agnes) during the last months of her life known as the: Last Conversations, among other books.
Now the other thing one must understand about autobiographies of Saints is that they are written, in every case, by someone who is extremely humble and in most cases was commanded to write under obedience. Thus they will leave out a great deal of the many miracles and amazing things they did in their life, but simply suffice with the amazing graces poured out upon them by God. This is fine, but one must understand that if they read an autobiography of a Saint they ought to then read a good biography of the same Saint to complete the picture.
Now for a brief list of books that fall into each category (with links to free copies available on the internet) that I have read and that I would highly recommend:
–Life of Saint Benedict, by Pope Saint Gregory the Great
–Life of Saint Malchus the Captive Monk, by Saint Jerome
–Life of Saint Hilarion, by Saint Jerome
–Life of Saint Paulus the First Hermit, by Saint Jerome
-Life of Saint Francis of Assisi, by Saint Bonaventure
–Victories of the Martyrs, by Saint Alphonsus Maria de Liguori
–Life of Teresa of Jesus, by Saint Teresa of Avila
-The Autobiography of Saint Anthony Mary Claret
-Divine Mercy in my Soul, by Saint Faustina Kowalska
Finally a few honorable mentions, which are some the very best biographies of Saints out there, which are impeccably researched and very deeply spiritually moving as well. They are not (as yet) written by canonized Saints, but their incredible worth does not allow for them to be omitted here based on the minor technicality. These books are:
-The Curé d’Ars: Saint Jean-Baptiste-Marie Vianney, by Abbé François Trochu (Official Biography)
-Saint Bernadette Soubirous, by Abbé François Trochu (Official Biography)
-The Story of a Life, by Guy Gaucher – Auxiliary Bishop of Bayeux and Lisieux (Official Biography of Saint Thérèse)
-The Passion of St. Thérèse of Lisieux, by Guy Gaucher (continuation of: Story of a Life)