Both of the books are very inspring and will invigorate your tefilah.
They are both meant to be read on a daily basis, with something new to read each day.
What I like about Book 2, is the first chapter deals with something very approrpriate to the times we live in, it is titled ” Tefilah: the Antidote for fear and Terrorism” regarding the Matzvav with the Yismaelim. How they act against us, it is because Hashem wants us to call out to Him, to save us from them. How they L;Havdil, proclaim things in the name of Hashem, how it should stimulate us to cry out to Hashem. That is a small bit.
The rest of the books are pretty much the same, just re-enforcing the basic principles of tefillah, to be read daily. Your tefillah and Emunah will definetly be changed for the better and you will understand why some of your tefillot, seemingly to you, do not appear to be answered, really are answered.