British psychologist Charles Spearman proposed a conception of intelligence perhaps most widely (though by no means universally) accepted by authors and users of intelligence tests. This chapter discusses Cattell and Horn's Gf-Gc Model, Carroll's Three-Stratum hierarchy, integration of Horn-Cattell and Carroll models to form CHC theory and applications of CHC Theory-Cross-Battery Assessment and Test Development. Stanovich argues for separating mental abilities measured by intelligence tests (MAMBIT) from other abilities, such as rational decision making, Sternberg's three components of successful intelligence, and Gardner's eight intelligences. Factor-based theories of intelligence have proliferated since Spearman started the ball rolling more than a century ago. The time has come for developers of individual clinical tests of intelligence to broaden their basis of test construction beyond the analytic dimension of Sternberg's triarchic theory and to begin to embrace the assessment of both practical intelligence and creativity.