Save Number of the Beast for last.
In it he brings together all the characters from his other novels, Stranger in a Strange Land, etc., even though they are from many different time frames. So if you read first it you might not know who some of these are.................
BTW, there is another version of Stranger In A Strange Land that was published a few years ago that is longer. The original, you might say. The one that was published in the 60’s was severely edited for length and content, but the original manuscript was ‘lost’ over the years until it was found in the garage of an editor who had died, by the son going thru his father’s stuff.....................
Nice, thank you.