be doing double-pass printing on both sides of each sheet, i.e. so that the page allocations look like:
[L] 40 1 [R] ---------------- --------------- sheet 1 [R] 39 2 [L]
[L] 38 3 [R] ---------------- --------------- sheet 2 [R] 37 4 [L]
....... .......
[L] 22 19 [R] ---------------- --------------- sheet 10 [R] 21 20 [L]
(where [L] and [R] refer to your description above). Or are you using a duplex printer which can turn the sheet over and print the next double-page on the other side immediately? If the latter there's no problem; if the former, and you have to go down [40,1] [38,3] ... [24,17] [22,19] and then turn these over and do [20,21] [18,23] ... [4,37] [2,39] then a slight modification of procedure may be needed.
Now these can be folded/cut down the middle and bound into a book. You might either cut each sheer very exactly down the middle and use a glue binder, or place the sheets on top of each other as shown above and sew (or otherwise fix) them together down the middle and then fold them.
In the latter case, a) You will need to guillotine the outside edges so that they are aligned flat, not bevelled (because of the thickness of the paper which pushes the inner sheets further out than the outer sheets). Then: b) It makes a much better job if, when you lay out the pages, you vary the page-offset (the gap from the left-hand margin) from sheet to sheet so that the distance from the righthand edge of the paper is always the same after guillotining off the bevel. What this means is that the central pages must be printed progressively nearer the centre-line of the sheet than the outer pages. This little detail is also readily arrangeable with groff (it's a rather professional detail, which you should find provision for in proper DTP/typesetting software, but would probably search for in vain in the likes of OpenOffice or Word. I don't know about Scribus). It may need some experimentation, though, in order to get it right (for which your trial copies, to be passed round the 5 or so friends for proof-reading etc., provide a perfect opportunity).
Come back if you want any further hints.
Best wishes, Ted.
-------------------------------------------------------------------- E-Mail: (Ted Harding) Ted.Harding@nessie.mcc.ac.uk Fax-to-email: +44 (0)870 094 0861 [NB: New number!] Date: 03-Dec-04 Time: 16:04:08 ------------------------------ XFMail ------------------------------