if "my space" was a brand, would they _really_ be able to forbid me to publish a book called "my space and time" based on that trademark ?
if they actually could, the world would be even sillier than previously thought. and I'd see it burn, gladly.
You can use a trademark in a title even when the book isn't about that trademarked product. There's a book titled "Amazon Warriors" which has nothing to do with Amazon. This is trademark fair use. Some trademarks create new words in order to avoid this possibility.
So no, a hypothetical "My Space" could not forbid you to write a book titled "My Space and Time". There are exceptions, like if there's a reasonable likelihood of confusion. For example, the title "My Space and Time Magazine Award Winner" is almost certainly a no-no because it implies endorsement which isn't present.