As an introduction to Gendlin’s philosophy the following text is recommended: Gendlin, E.T. (1973). Experiential phenomenology. In M. Natanson (Ed.), Phenomenology and the social sciences. Vol. I, pp. 281-319. Evanston: Northwestern University Press. The text is available at www.focusing.org/gendlin/docs/gol_2101.html
There are important elements in it from his first big philosophical work ‘Experiencing and the creation of meaning’ (1962).