I second the 39 steps and Just William suggestions. Perfect.

There's a lot to be said to just walking into a library and picking out a book from the crime section that doesn't have pink/swirly writing on the cover - if they've got into print then they're not going to be that bad.
Yesterday I got 'Started Early, Took My Dog' by Kate Atkinson. Never heard of her, never heard of it but if I get half way through and don't get on with it I don't lose anything when I take it back.

Pretty much any of the early Forsyth is worth a read, 'The Odessa File' is worth it just for the twist in the ending. If the OP wants to try a short story then 'No Comebacks' or 'The Shepherd' are an easy start too.