I have a 1997 Cherokee that will start in any gear. I would appreciate any information about what might be causing this problem and how to fix it.

 

Sounds like either a bad neutral safety switch (NSS) or a short in the wiring for the NSS. The NSS (aka: Range sensor) tells the computer what position the gear selector is in and prevents starting except in "N" or "P".

 

Or someone bypassed it. Might look for a jumper in the connector. 97 should set a code if it's bad, shorted or bypassed.

 

Like was said above, sounds like your neutral safety switch is either bad or bypassed.