A few quotes from Ian Fleming’s Casino Royale (1953) about James Bond’s clothing:
“As he tied his thin, double-ended black satin tie, he paused for a moment and examined himself levelly in the mirror.” (Chapter 8)
“He looked carefully round the room to see if anything had been forgotten and slipped his single-breasted dinner-jacket coat over his heavy silk evening shirt. He felt cool and comfortable. He verified in the mirror that there was absolutely no sign of the flat gun under his left arm, gave a final pull at his narrow tie and walked out of the door and locked it.” (Chapter 8)
The first quotes about the clothes in Ian Fleming’s books are about Bond in black tie, which is what we also first see Bond wearing in the films. The scene in the 2006 film Casino Royale where Bond admires himself wearing the dinner jacket he got from Vesper in the mirror also recalls this scene, though Bond in the book already knew how to wear a proper dinner jacket and did not need help from Vesper. We don’t know what colour his dinner jacket is, if it’s black, midnight blue or cream, and we don’t know any of the specific details. Shawl collars were the most popular style in the era, but peaked lapels could have also been a possibility.
Fleming also describes Bond’s beachwear and casual dress later in the book:
“Bond walked along to his room and sat down on the bed. He felt weak from the passion which had swept through his body. He was torn between the desire to fall back full-length on the bed and his longing to be cooled and revived by the sea. He played with the choice for a moment, then he went over to his suitcase and took out white linen bathing-drawers and a dark blue pyjama-suit. Bond had always disliked pyjamas and had slept naked until in Hong Kong at the end of the war he came across the perfect compromise. This was a pyjama-coat which came almost down to the knees. It had no buttons, but there was a loose belt round the waist. The sleeves were wide and short, ending just above the elbow. The result was cool and comfortable and now when he slipped the coat on over his trunks, all his bruises and scars were hidden except the thin white bracelets on wrists and ankles and the mark of SMERSH on his right hand. He slipped his feet into a pair of dark-blue leather sandals and went downstairs and out of the house and across the terrace to the beach.” (Chapter 23)
“He dried himself and dressed in a white shirt and dark blue slacks. He hoped that she would be dressed as simply and he was pleased when, without knocking, she appeared in the doorway wearing a blue linen shirt which had faded to the colour of her eyes and a dark red skirt in pleated cotton.” (Chapter 24)