Yes, I'm going by the first letter of his first name rather than by last name. Either way, I say it's okay for me to do that, and I'm going to do it anyway.
Isaac Newton contributed greatly to scientific understanding. Neil deGrasse Tyson credits him with being the greatest physicist of all time, so that's a good endorsement as far as I'm concerned.
Here's a brief biography about Isaac Newton with the briefest of overviews of his work.