I used to be in the book biz and knew the numbers by heart, but here's the best I can recall. Note that like in all business EVERYTHING IS NEGOTIABLE.
Standard author royalty = 10% of list price but is quickly bumped to 15% to get a proven author, or one who has a decent agent, or for dual authors.
Another 15% goes for production costs: author acquisition and hand holding, editing, typesetting, photography, cover art work, releases, etc. This cost is all amortized over the first printing which makes subsequent printings 15% cheaper.
Another 10% goes for printing costs. Add $1/book cost for a hard cover (a BIG profit item.)
Another 15% goes for marketing/promotion. This could go higher to launch the first printing.
So here is how typical numbers might look for a quality $20 book: This $20 book will be sold in small to medium quantities to retailers for 40% off the sticker price, or $12. (For large quantities they will demand 50-60% off sticker. You can see why the incentive to sell by direct mail or whatever is very strong to escape the discounting.)
Author gets $ 3
Production cost $ 3
Printing cost $ 2
Marketing cost $ 2
That leaves $2 for the publisher to cover all other expenses including office, salaries, rent, utilities, travel, etc. If there is anything left it is called PROFIT, on which taxes must be paid. (Note that after the 1st printing there will be an extra $3/book available due to no Production cost.)
Across the industry, a first printing of 10,000 copies is considered large. 3,000 to 5,000 copies is more typical. The definition of a "successful book" is one which sells out it's first printing thereby paying all the bills related to it. Only a small percentage do so.
But let's assume a first printing of 10,000 copies. (I never did smaller, and many were much larger.) If completely sold out that would create gross revenue of $200,000. At 40% discount the publisher would get $120, 000 to pay all the bills.
As publisher you will gouged mercilessly by the large retailers who will demand 90 to 120 days to pay you for the books they order. Any books in their store which are not sold when payment is due will be carelessly dumped in boxes and shipped back to you to avoid payment. These books will be damaged in the process of careless shipping so become worthless scrap. But at the same time these same retailers will reorder the same books from you, again demanding with 90-120 days to pay, to replace those they just returned to you. For better placement in their stores expect to pay.
Publishing of books, magazines, newspapers and software is an extremely profitable business IF things go well and you have best sellers. Once the up front producton costs are paid, it's just a matter of "duplicating" the product at a very low unit cost. This is quite unlike being in the manufacturing business where the actual product cost is high.
Please note that my numbers are dated (and my memory probably defective), but I think the percentages and allocations are in line. Hopefully the arithmetic added up. Maybe someone in book publishing today would care to tweak these numbers further.
Is this what you had in mind???