True Friendship by Vaughan Roberts: Book #35 for 2018
I reviewed this book not long ago - see https://50bookchallenge.livejournal.com/13614716.html
I decided to read it again; it's quite short, and I enjoyed reading Vaughan Roberts' views on friendship and also marriage from a Christian perspective. There are many liberals who would not agree on his anti-gay marriage stance, though.
I found the book mostly challenging in that it set out that friends need to be honest with each other, and often if the truth is going to hurt, I find it difficult to tell a friend without at least attempting to be diplomatic. The book uses a lot of quotes from Proverbs to back up its arguments.
As mentioned before, Roberts' opinions are likely to stir up some controversy, but this book is a really easy read, and can be read in probably less than an hour.