Present routine strength testing of commercial paper employs one or more practical tests which simulate product failure conditions. Burst, tear, and fold tests are illustrative. Although the usefulness of such tests is beyond dispute, their weakness lies in the fact that they are nondiagnostic. That is, although a paper sample can be characterized as, say, below specification, the test does not provide information as to why the paper is weaker than normal. Without such knowledge, correcting the problem necessarily demands the trial and error approach. Shortspan tensile analysis is a new approach designed to provide diagnostic information in a rapid and economic manner. The essence of short-span tensile analysis is to observe the change in sheet tensile strength in the span range from 0 to about 0.5 mm, both in the normal dry condition (bonded) and also in a wet (unbonded) state. The evaluation of such data provides parameters of basic fiber strength, fiber length, fiber orientation, and degree of bonding. The concepts underlying short-span tensile analysis are summarized and a number of practical examples of the use of this kind of analysis for diagnosing laboratory handsheets and commercial papers are presented. -- AATA