Thank you Kappy and Dahveed for your help. I probably should have been more specific. I have a both an iPad as well as an iPhone in addition to a Mac Book Pro.
I purchased a book in Mobi format from an online retailer that was not Amazon. I downloaded it to my Mac Book. I then dragged the downloaded file from "downloads" to the "send to kindle" app on my Mac Book. The Book syncs up with my iPad and my iPhone but not my Mac Book.
All content purchased through Amazon syncs perfectly and shows up on my Mac Book kindle app. The content not purchased through Amazon syncs perfectly with my iPad and iPhone but will not sync with my Mac Book kindle app.
I was told by Amazon customer service I had an outdated version of the Kindle app and that was the reason. They said I had to go to the apple store to get the most up to date version. This ofcourse was not correct as shown by both Kappy and Dahveed.
I have since gone to the Kindle down load link at the Amazon website as provided by Kappy
http://www.amazon.com/gp/feature.html/ref=kcp_mac_mkt_lnd?docId=1000464931
This application is a more current version than I had but it still does not allow me to sync a book purchased in Mobi format from a non Amazon retailer.
Anyone have any further insight into my problem?
Dahveed, you said you use these apps. Do you have any other useful information that can solve my issue?