Who is the real God?

Had supper at my daughter's on Sunday.

I took the the chocolate and almond cake
made from "How to Master the Art..." Julia Child. Iced with choc/butter and topped with blanched halved almonds

There was a 'belief' discussion got me thinking.

Next day Simon Sebag Montefiore's book Jerusalem was discussed "..the universal city, the capital of two peoples, the shrine of three faiths, the site of Judgement Day and the battlefield of today’s clash of civilizations. From King David to Barack Obama, from the birth of Judaism, Christianity and Islam to the Israel–Palestine conflict..."

then I found a web site "Why Jews don't believe in Jesus"
Is there a God, is there only one with different names?