I couldn't agree more with Bindicat, on all her comments actually.
The reason why I made a point of saying that you should get the Vatsyana edition is that it starts off by assessing and grouping men and women into 9 distinct categories depending on:
Size
Stamina
Passion
There are three distinctions he made, some 3,000 years ago if I am not mistaken, and they hold true to this very day.
For size, there is Hare, Bull and Hores for men and Deer, Mare and Elephant for women. It then goes on to discuss the advantages/disadvantages for all combinations. Further along, you'll find a description of which positions work best in both equal and unequal unions.
It does take a bit of thinking about what was written as it is not the straight forward 'User Guide' 21st century readers might be looking for but it has the great advantage of nor solely lingering on the subject of intercourse, which is probably just as well, as during a lifetimes partnership, you are unlikely to spend 95% of your time between the sheets.
It definately gave us some great ideas about what to get up to in our more private moments. The chapter on caressing each other is phantastic, as is the one about embracing, something at least my wife loves.
If I can find a PDF copy of it I will post a link here, so long as that is permissible. That way you can have a quick read and then decide at your own leisure if it would be something you'd be willing to buy.
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Update:
Not a PDF copy but something completely legal, part of the Project Gutenberg Collection. This is:
The Kama Sutra of Vatsyayana
Translated by Sir Richard Burton (Yes, the African Explorer)
First Published in 1883 (my mistake with the 1878 version, I just checked)
This Edition published in 1963
The Project Gutenberg eBook of The Kama Sutra of Vatsyayana, by Richard Francis Burton, Bhagavanlal Indrajit, and Shivaram Parashuram Bhide.
I don't like reading books on the computer but there is no other way here. Just remember, if you enjoyed it, buy it. Just make sure it is the WHOLE Kama Sutra, not one of those that only come with pictures and instructions on how to penetrate, since you'll lose the best part of the book.
Happy reading.