George Kelly born April 28, 1905-March 6, 1967 was an American psychologist, therapist, educator and personality theorist. He is considered the father of cognitive clinical psychology and best known for his theory of personality, Personal Construct Psychology. During his school years and his early professional career, he dabbled in a wide variety of jobs, but he eventually received a Ph.D. in psychology from the State University of Iowa.  He began his academic career at Fort Hays State College in Kansas, then after World War II, he took a position at Ohio State. He remained there until 1965 when he joined the faculty at Brandeis. He died two years later at age 61.

Kelly believed that people interpret events according to their personal constructs rather than reality. Person as a scientist , these are the people attempt to solve problems in much same as the scientists. They observe , ask questions , formulate hypothesis and making conclusions.Scientist as a person , Because scientists are people, their pronouncements should be regarded with the same skepticism as any other data. Every scientific theory can be viewed from an alternate angle, and every competent scientist should be open to changing his or her theory. Constructive Alternativism , Kelly postulate that our experiences of the world around us, including events that take place or our understanding of people, including ourselves, are open to an immense variety of interpretations. Kelly argued that no one construct a final or definitively accurate way of grasping the world. Instead, we can always create alternative constructs to better explain or represent that which we observe.  He also developed shape behavior that they create and attempt to fit over realities of the world. First is Basic Postulate , it assumes that human behavior is shaped by the way people anticipate to future and it has 11 supporting corollaries.

·         The construction corollary: "a person anticipates events by construing their replications." This means that individuals anticipate events in their social world by perceiving a similarity with a past event (construing a replication).

•       The experience corollary: "a person's construction system varies as he successively construes the replication of events."

•       The dichotomy corollary: "a person's construction system is composed of a finite number of dichotomous constructs."

•       The organization corollary: "each person characteristically evolves, for his convenience in anticipating events, a construction system embracing ordinal relationships between constructs."

•       The range corollary: "a construct is convenient for the anticipation of a finite range of events only."

•       The modulation corollary: "the variation in a person's construction system is limited by the permeability of the constructs within whose range of convenience the variants lie."

•       The choice corollary: "a person chooses for himself that alternative in a dichotomized construct through which he anticipates the greater possibility for extension and definition of his system."

•       The individuality corollary: "persons differ from each other in their construction of events."

•       The commonality corollary: "to the extent that one person employs a construction of experience which is similar to that employed by another, his psychological processes are similar to the other person."

•       The fragmentation corollary: "a person may successively employ a variety of construction subsystems which are inferentially incompatible with each other."

•       The sociality corollary: "to the extent that one person construes the construction processes of another, he may play a role in a social process involving the other person."

After many years in his clinical experienced he enabled to evolve the concepts of Abnormal development and psychotherapy , and REP test Role Construct Repertory. Abnormal Development

A. Abnormal Development
Kelly saw normal people as analogous to competent scientists who test reasonable hypotheses, objectively view the results, and willingly change their theories when the data warrant it. Similarly, unhealthy people are like incompetent scientists who test unreasonable hypotheses, reject or distort legitimate results, and refuse to amend outdated theories. Kelly identified four common elements in most human disturbances: (1) threat, or the perception that one's basic constructs may be drastically changed; (2) fear, which requires an incidental rather than a comprehensive restructuring of one's construct system; (3) anxiety, or the recognition that one cannot adequately deal with a new situation; and (4) guilt, defined as "the sense of having lost one's core role structure."

B. Psychotherapy
Kelly insisted that clients should set their own goals for therapy and that they should be active participants in the therapeutic process. He sometimes used a procedure called fixed-role therapy in which clients act out a predetermined role for several weeks. By playing the part of a psychologically healthy person, clients may discover previously hidden aspects of themselves.

C. The Rep Test
The purpose of the Rep test is to discover ways in which clients construe significant people in their lives. Clients place names of people they know on 
a repertory grid in order to identify both similarities and differences among 
these people.

Interpretations are always available to people.