In 1978, Fritz Klein makes the Klein sexual orientation grid (KSOG). It was in his book "The Bisexual Option". The KSOG uses a seven-point scale to measure sexual orientation in seven sections. The focus is on three different points of life: past (from age thirteen to one year before current age), present (within the last twelve months), and ideal (what someone wants if they have complete choice). This design is an improvement on the Kinsey scale.