Well according to Shatner they hadn't spoken in 5 years, that is what he said at the time of Nimoy's passing. So he passed in 2015 so if it was 5 years they would have stopped speaking sometime in 2010. There is a lot of back and forth about why it happened. Bill says he feels it might have been because he was involved with a ST Captain's gathering and Leonard didn't want to be part of it, he was there and a film crew had him in shots and he got mad and that was why he didn't speak to Bill. I'm not sure if that is the case. As I said only Leonard knew for sure why he stopped speaking. Before that they were thick as thieves. ST events brought them together plenty of times. Also they appeared together (aside from ST) in TJ Hooker and Priceline commercials. Both shows were Bill's projects and he involved Leonard in them.
I read Bill's book about Leonard. There are plenty of nice stories about them, their struggles while shooting the original series and movies. And how Leonard flew them both to Lake Tahoe where Leonard had a place.
