1. Yes, you want to mow the lawn very short before reseeding and then rake it to get rid of any thatch and debris. This loosens the surface so the seeds make contact with soil.

2. In my area, I recommend covering with a thin layer of screened compost. Or good garden soil. This helps hide the seeds from predators (birds) and keeps them moist. Don't use peat moss for this purpose as it dries out too easily and then becomes water repellant.

3. The fertilizer at this point is optional, IMO. If you go that route, the compost provides adequate nutrients to get things started but seeds don't really need any fertilizer immediately. Wait until it is up and ready for its first mowing, then fertilize. And yes, organic fertilizers are preferred (especially in an Organic Lawn Care forum :-)) and are by nature slow release.

Be sure to keep the overseeded lawn consistently moist - not wet - until germination.

1. Cutting grass that has been growing at about 4 inches down to 1/2 to 1 inch will cut off so much of the blades, that are used to manufacture nutrients that feed the roots to promote good healthy growth, that the turf now growing there will be weakened quite a bit. While at one time this recommendation was common most lawn experts stopped recommending that 25 or 30 years ago. There are still some that do still follow that bad advice, however.
2. If the seed needs to be covered a thin layer of compost would be much better then Peat Moss.
3. Until the grass is up and growing it will not need any "fertilizer" and spreading some before then is simp0ly a waste of your time, energy, and money since there is a good chance what you put down could be washed away by any rain you might get.

While at one time this recommendation was common most lawn experts stopped recommending that 25 or 30 years ago. There are still some that do still follow that bad advice, however.

You might want to re-check your sources. This is still very much an accepted practice for fall overseeding with tall fescue (and with most other cool seson grasses for that matter). It is critical that the seed make contact with the soil and the close mowing achieves that. It also reduces the competetion from the established turf. Under 1" may be a bit excessive but you definitely want to bring it down below 2" or use your mower's lowest setting.

Unless you are dealing with bermuda grass, every source you find, including various extension publications (not that they are always cutting edge), recommend this practice for fall overseeding.

Most of the sites I find on the 'net do talk about cutting turf grasses quite short but they are also not from any research people, only those that maybe, possibly learned about lawn care long ago. The current information from the turf grass people at Michigan State, according to what they tell me, is mowing a lawn short is not a good idea as I explained above.
In a properly cared for lawn thatch will not be a problem, but if enough is present it should be taken care of before over seeding. If there is some concern the seed will not make good ground contact perhaps using a slit seeder should be considered.
Generally, I've not found over seeding to be of much benefit in a properly cared for lawn.

Here is a link that might be useful: Michigan State on overseeding

I don't know what to tell you, kimmsr, except that maybe you need to do more research before you start saying that information an experienced horticulturist is providing is "bad advice".

Since you put so much store in the validity of the research behind extension service information, a simple search will show that most state exactly what was told the OP and what I reinforced - the lawn should be mowed very short before overseeding. If you want to verify yourself, take a look at the overseeding/lawn renovation info sheets provided by Clemson, IA State, OK State, WSU and UMD just to get you started.

While I agree that the recommended length of 1/2 to 1 inch seems incredibly low for tall fescue, EVERYTHING I've seen recommends cutting the turf down so that the seed can reach soil.

Kimmsr, you are right to say that healthy soil and healthy plants, usually achieved through proper horticultural practices, are much less problematic. However, that has nothing to do with overseeding tall fescue, which naturally thins out in patches regardless of the health of the lawn. Anyone with tall fescue knows this...

For many years now lawn care "experts" have told us to never cut more then 1/3 of the grass at any one time because that will weaken the grass by depriving it of the ability to manufacture the nutrients the grass roots need to grow more grass plants. If that is true then simple logic says cutting grass, that was growing 3 inches high, to 1 inch is not a good thing to do no matter what.
Many years ago I did over seed the lawn, but I did not cut the grass shorter than normal and had no problem. I have also since thought that the whole concept of over seeding benefits the seed companies more then my lawn. Turf grasses growing in a good healthy soil will spread and, in my experience, about as fast as over seeding would.

The recommendation for removal of only 1/3 of the lawn height is for regular mowing, not for overseeding. This is a unique, one time situation when short mowing is of benefit. A single, very short mowing is not going adversely affect the existing turf

There are all kinds of perfectly good reasons why overseeding is advised. Many cool season grasses are bunch grasses and they do not spread via rhizomes (eg. the tall fescue). In time, these types of lawns can become thin and overseeding helps to make the lawn dense and lush. Excess foot traffic can also wear out grasses and offer the need for overseeding to rejuvenate. Older lawns have often been seeded with inappropriate grass types, like KBG in western states and these grasses die out, leaving the lawn spotty and uneven. Often, site conditions like slopes or shade or adjacent large trees are just not conducive to lush lawn development and routine overseeding is needed to keep these tough areas looking good. And many warm season lawns are routinely overseeded with a cool season seed in late fall to maintain a uniform, year-round green appearance. Not to mention all the occasional cultural issues that can crop up like a weed infestation or a disease or insect problem that can create a spotty, weak lawn from time to time.

So making broad statements like grass growing in a healthy soil should not need overseeding is indicating a gross unawareness of the many varied and valid reasons why overseeding is an accepted lawn maintenance practice.

Logic fails.

Thanks Gardengal for your concise explanations--I will now be over seeding some areas in the lawn in the near future--after I mow on the lowest setting.

I've been waffling whether or not to do this and now I have no reservations!