It is very hard to interpret retrograde planets in a chart, particularly if you don't have any retrograde planets yourself. You will find that there is very little written about the interpretation of retrogrades and Schulman has done a very fine job of explaining the energy of this phenomenon in his book.
Every book in the series is excellent and together they make a nice "set" edition to your astrological reference library.
Mr Schulman was the first astrologer that gave me a balanced understanding of my retrogrades planets. I now feel a lot more comfortable with their effects in my life. He is very thorough and insightful about the the energies that they represent and how they should be used. I'd always read that they were a big burden for me to carry but I now know that they are indeed a gift for me to use in working on my karmic challenges.