The secret of the "Non-loop method", which advances the scope without creating a loop and applying tension to the intestinal tract, is fully disclosed. This is a must-read book for colonoscopists who aim for pain-free, safe and high-quality inspections. Focusing on the first and final flexions of the sigmoid colon, the insertion method that does not create a loop is patterned in four steps, and illustrated and verbalized so that even beginners can easily understand it.