The Institutes of the Christian Religion (Kindle edition) by John Calvin.
This edition of Calvin's Institutes of the Christian Religion is from the translation made by Henry Beveridge in 1845 for the Calvin Translation Society. It also includes a Forward by John Murray, who was Professor of Systematic Theology at Westminster Theological Seminary.
I wanted an electronic edition of the Institutes to use as a reference. I did look at some other Kindle editions of the Institutes and found them lacking the interactive table of contents necessary for a usable reference work. This Kindle edition more the adequately makes up that deficiency. I really appreciate the quick navigation and browsing capability, and am very satisfied with this purchase. At $ 0.99, the price was right.