Apart from some early writings, none of these books were actually written by him. They are transcribed from spontaneous talks he gave almost daily for around thirty years. Those talks, or discourses, were recorded on audio and later also video. Each of those talks was part of a series, and became a chapter in a book with the title of that series.
The books listed in the above links are those original books. Titled and designed by Osho, they are are pure and unabridged.
There are a number of newer titles, issued since Osho left the body, which are edited and abridged compilations culled from the original books. They are usually titled ‘Osho on ...’, and do not have his photo on the cover.
Osho has always taken personal interest in the design and appearance of his books. For example, the cover for this booklet from the sixties (with the arrows) was created by him.
Osho insists that his books are produced only in hard cover – he says they are not like paperbacks, to be read once and then thrown away. And he chose the photos of himself which he wanted to appear on every front cover. He also designed the logo for Rebel Publishing, the sannyas publishing house, and he also chose the gold and silver embossing on the covers that makes his books glow.
Right up until a few nights before he left the body, Osho was choosing photos for the covers of his books and giving input for their design.