The Diary, kept by Saint Faustina, is the source of all information regarding The Divine Mercy Devotion.
The internet is, of course, a source of much information about The Diary and Its Contents.
The following curated sites are highly recommended for reasons given below...
This site is suggested because it has a nice page flipping action that many will appreciate.
          Click on "Full text of Saint Faustina's "Diary".
This site is suggested because it has a typical website text layout.
          Scroll to read; you may enter a page number to jump to if you wish.
This site is suggested because it offers a free version of the diary in several e-formats.
          Free registration is required to download The Diary.
This site is suggested because it has a menu listing the 5 Devotions.
          You can easily read about any devotion.
Informative introductory material.
Complete as it covers the 5 independent elements of the devotion.
Calls out the graces offered with each devotion.
Daily guide for the Divine Mercy Novena of Chaplets
so you can make the nine day novena.
Quoted paragraphs are keyed to the Diary.
The Devotions are presented in a unique visual and auditory style
which is available for free on this website.