Our book is based on Scribus v 1.3.6, and I have both Scribus v 1.3.6 and Scribus v 1.4.
Everything in the book works for both Scribus v 1.3.6 and Scribus v 1.4.
Most if not all of it applies to Scribus v 1.5 also.
You can learn how to design book cover by just looking through the color screenshots in our book. We use our book as an operation manual in our office also. Our goal is to make Scribus as easy to use as a telephone.
Gang Chen, Author, AIA, LEED AP BD+C