This is an excellent edition of two works by John Locke that are necessary to understand his philosophy. Of the Conduct of the Understanding is one of the most important works by Locke, and is often overlooked by Locke scholars. In it, he succinctly explains his worldview that is behind his other writings (esp. The Essay, but also works such as the Two Treatises, etc.). This is a must read for anyone wanting to understand Locke's philosophy.
Some Thoughts Concerning Education is also an important work to understand what kind of citizen he envisioned should make up civil societies. These are a collection of letters he wrote to a friend about raising children. In it, we can see what kind of training children require to participate in civil society, according to Locke.
Also, by reading both works, the reader can see how Christian ideas are an important foundation of Locke's worldview.
I highly recommend this edition of these works by Locke!