This is a charming little book by Kitson. It's only 76 pages, perfect for a beginner. He references Prout's book on fugue several times, so If your looking for an more exhaustive treaty look there. You are to read Kitson's Invertible Counterpoint and Canon before this book as well as understanding basic counterpoint and harmony. Have the Bach 48 Prelude and Fugues on hand as he references them throughout the book. I had no problem following the examples given in the text since he marks what you are to be looking for.
Contents The Subject 9 The Answer 16 The Counter-Subject 28 The Exposition and Counter-Exposition 42 Episodes 55 Middle Entries 62 The Final Section and Stretto 72