The book Gita Wisedom is good for those who have not read any full version of the Bhagvad Gita. Wish short and easy meaning of the Gita verses given out in the book makes it a comfortable read, avoiding the usage of technical details. Wherever, the author could not escape using them, he has well explained the concept in footnotes.
One thing that I would like to have seen is Joshua explaining the concept of the titles of different chapters of Gita i.e. Sankhyayoga, Karmayoga, Gyankarmasamyasayoga, karmasamyasayoga, aatmasamyamyoga and so on for all the eighteen chapters, and why they were named so. It would have helped the reader understand the very purpose of Bhagvad Gita.