"Now normally, except for special reasons, Greek nouns always have the definite article in front of them...when a Greek noun has not got the article in front of it, it becomes rather a description than an identification, and has the character of an adjective rather than a noun. We can see exactly the same in English. If I say; 'James is the man', then I identify James with some definite man whom I have in mind; but, if I say; 'James is man', then I am simply describing James as human, and the word man has become a description and not an identification. If John had said 'ho theos en ho logos', using a definite article in front of both nouns, then he would have definitely identified the logos with God, but because he has no definite article in front of theos['God'/'god'] it becomes a description, and more of an adjective than a noun. The translation then becomes, to put it rather clumsily, 'The Word was in the same class as God, belonged to the same order of being as God'...John is not identifying the Word with God. To put it very simply, he does not say that Jesus was God."- William Barclay, Many Witnesses, One Lord, 1963, pp.23,24.
For more on John 1:1 see here.