Ludwig Binswanger, Medard Boss, R.D.Laing, Emmy van Deurzen) attempted to create therapies sensitive to common "life crises" springing from the essential bleakness of human self-awareness, previously accessible only through the complex writings of existential philosophers (e.g., Søren Kierkegaard, Jean-Paul Sartre, Gabriel Marcel, Martin Heidegger, Friedrich Nietzsche). The uniqueness of the patient-therapist relationship thus also forms a vehicle for therapeutic inquiry. A related body of thought in psychotherapy started in the 1950s with Carl Rogers. Based also on the works of Abraham Maslow and his hierarchy of human needs, Rogers brought person-centered psychotherapy into mainstream focus. The primary requirement was that the client receive three core "conditions" from his counselor or therapist: unconditional positive regard, sometimes described as "prizing" the client's humanity; congruence [authenticity/genuineness/transparency]; and empathic understanding. This type of interaction was thought to enable clients to fully experience and express themselves, and thus develop according to their innate potential. Others developed the approach, like Fritz and Laura Perls in the creation of Gestalt therapy, as well as Marshall Rosenberg, founder of Nonviolent Communication, and Eric Berne, founder of transactional analysis. Later these fields of psychotherapy would become what is known as humanistic psychotherapy today. Self-help groups and books became widespread. During the 1950s, Albert Ellis originated rational emotive behavior therapy (REBT). Independently a few years later, psychiatrist Aaron T. Beck developed a form of psychotherapy known as cognitive therapy. Both of these included relatively short, structured and present-focused techniques aimed at identifying and changing a person's beliefs, appraisals and reaction-patterns, by contrast with the more long-lasting insight-based approach of psychodynamic or humanistic therapies. Beck's approach used primarily the socratic method, and links have been drawn between ancient stoic philosophy and these cognitive therapies. Cognitive and behavioral therapy approaches were increasingly combined and grouped under the umbrella term cognitive behavioral therapy (CBT) in the 1970s. Many approaches within CBT are oriented towards active/directive yet collaborative empiricism (a form of reality-testing), and assessing and modifying core beliefs and dysfunctional schemas. These approaches gained widespread acceptance as a primary treatment for numerous disorders. A "third wave" of cognitive and behavioral therapies developed, including acceptance and commitment therapy and dialectical behavior therapy, which expanded the concepts to other disorders and/or added novel components and mindfulness exercises. However the "third wave" concept has been criticized as not essentially different from other therapies and having roots in earlier ones as well. Counseling methods developed include solution-focused