Hi
It is always possible to be faster with a method than has been achieved before. So yes, logically faster than 37 secs must be possible with that book. Another matter is that 37 secs is not at all fast by todays standards. So without knowing the method/algorithms in the book it's not the one to go for if you wanna be a top 3x3x3 speedcuber
Have fun!
-Per