In the second edition of this hugely popular book, Tony Merry reorganised and updated the text to include the latest initiatives in the world of counselling and psychotherapy. It offers in-depth discussion of all aspects of person-centred counselling from its origins to current developments in theory and practice.
The late Tony Merry wrote in plain English, so it's an easier way to get one's head around the theory, rather than getting caught-up in scientific psychobabble. Clearly, I believe in Carl Rogers' theories, otherwise I wouldn't have spent the past four years training in his style of counselling, but he was ultimately a scientist and some of his theory does get a tad complicated for my non-scientific brain.
Learning and Being is an intermediary text for counselling trainees. It covers the basic issues, but does so in more depth, and with a greater appreciation for the ranges of alternative opinions, than do some of the other introductory books I've read.
Some good mental/emotional exercises are included too.