As good a handbook on meditation as I've ever seen. I use the trick of concentrating on the breath if my mouth is filling with saliva or some other bodily sensation is threatening to disturb my peace. Not to think about the breathing, just watching it happen.
And I watch the thoughts go by in exactly the same way. With even more detachment. They are not my thoughts. I am the observer. These things arise like clouds and pass by, and it's best to ignore them. Certainly not to believe them.