The Mars Book is an app that is dedicated for observing Mars which will make close approach in autumn 2020. Mars will come close to Earth from September 2020 through October 2020. Closest approach will take place on October 6, 2020. Mars Book is a highly useful Mars observing app which will indicate the location of Mars visible in the sky. It shows you why Mars Close Approach will take place, and it is explained readily using animated illustrations and star charts at a viewpoint from outer Space. Mars Close Approaches taking place 23 times from the year 2003 through 2050 will be displayed and apparent retrograde motion of Mars will be displayed. Enjoy Mars Close Approach this summer with the Mars Book app!