Volume 6 of Charlotte Mason's Original Homeschool Series paraphrased sentence by sentence into plain English by Leslie Laurio. If you can only read one volume of Charlotte Mason's series, this should be the one, since this volume details the long-term vision and goals of CM that parents will need to understand the why's of the method, as well as covering curriculum considerations for all ages. You can also read this book online for free at
I would recommend the book by Charlotte Mason that is in her own words. The modern English version did not help me that much, and was very confusing because they included the page numbers from the original book in the newly translated one. Probably a help to find the similar passage in the original book.... but very difficult to navigate in the new edition!