Why is God not always mentioned?

When I read some things about Judaism, God is not always mentioned.  Do these writers think God is not important?  In one quote I have just read, Judaism is explained without any reference to God!

Rabbi Jonathan responds

I am not sure the exact quote you referred to, and I am sure that when you find references without a direct reference to God, in the main, it is because a belief in the ultimate power is implicit, though how immanent and interventionist this 'God' may be varies from person to person and between contexts and cultures.  

As you may know, there was an influential Rabbi called Mordechai Kaplan (1881-1983), who in 1934 qrote the important book Judaism as a Civilization .  He eventually co-founded a significant new and quite intellectual Jewish group called Reconstructionists.  Many accused him of denying God, but I think that was a misinterpretation - he had a more naturalistic conception of God - and certainly Reconstructionists today tend (in defence?) to emphasise a belief in God - but certainly the 'modern God', at least of the Progressive/Reform/Liberal/Reconstructionist Movements  is not the old (super) 'man on the cloud with a beard' interventionist God depicted by the Torah's anthropomorphisms (using human language to describe something, such as a dog smiling, or God's outstretched arm or back or nostrils), and painted into visuals by Michelangelo!   

I have a lovely story (in a Progressive machzor - High Holyday prayer book)  about a man who was so impatient to find God that he didn't stop to recognise the divine, until eventually a wise Rabbi showed him hospitality instead of trying to directly answer his question 'where will I find God' - slowly he became a part of the community... and one day the Rabbi said 'I think you have found God now, have you not?' and the man answered 'Rabbi, I think I have, but I am not sure when, or where - and tell me Rabbi, why is God in this place only...?'.  

So rest assured, God is in this place - in a Progressive approach to Judaism! But God may not always have quite the same profile and exposure that you might find in other places.  We also put a lot of emphasis in Judaism on our own responsibilities, through mitzvot (commandments). We often see the relationship as 'shutafut' (a partnership) between humans and God - we are God's 'tools' or 'hands' in the world.