What's the Name of That Book??? discussion

So I must have read this book during high school, some time around 200-2004, pretty sure the book was an old one even at that time. I've searched through the internet and in this group. I came across https://www.goodreads.com/topic/show/... already and was hopeful the book would be there but none of those match my memory.

The book took place in the pretty distant future, man kind has made its way all throughout the galaxy (and further?). This was possible through the discovery of some kind of alien plant or tree that formed a telepathic type network spanning space. I think any one was able to communicate, all that was needed was to be touching the plant. They were rare, one for a few per planet/expedition maybe?

There were also some robots that were discovered along the way. These were multi-legged crawling type robots, I think similar to a spider or something. The origins of the robots were unknown. Humans were unable to access/diagnose/understand the robots. There was also no meaningful communication with the robots. I think they mostly just functioned as "pack animals".

(view spoiler)[
At the end of the first book something happens to the protagonist when trying to communicate after discovering something in a distant planet or something. Either the plants sort of broadcast some sort of warning and/or all the communication stops.

Something also happens with the robots, either they all stop following orders and go into a worrying mode or something else foreboding.
(hide spoiler)]

A long shot - Fifth Planet by Fred Hoyle? There are different cover images.

Worldcat.org - "Fred Hoyle's scientific pedigree is up front in this vintage novel, co-written with son Geoffrey. The story is based on a classic SF premise--a star, with its own planetary system, is heading towards our own. It passes close enough for us to mount an expedition to one of the planets of the visiting star--an earth-like world with detectable signs of plant life. The planet turns out to be inhabited by vastly superior telepathic beings who hide themselves from the visitors. One of them takes possession of the mind of an astronaut, returning to earth to spread a dramatic and unwanted telepathic warning against the nuclear arms race, before returning on a hijacked spacecraft."

Manuel, does the story begin on Earth? Who are the main characters and where are they from?

Hey Kris,

Thanks but nope Fifth Planet isn't it. I don't recall any character's name. I _think_ the main story line/character was a male, but maybe not the only story line. I think it was all humans (or at least I can't recall any alien life forms (besides the trees)). Earth was only mentioned as back story that humans had developed technology to traverse space and have been doing so for a long time now.

Kevin J Anderson's The Saga of the Seven Suns?

Cycad, I'm 90% thats it! I'm not recalling all the other races/life-forms but the green-priests sounds like its it. I also think I recognize the cover art. Definitely going to take the first book for read!

Here's the Google Books preview of Hidden Empire (The Saga of Seven Suns series, #1) by Kevin J. Anderson - Cycad's suggestion:

https://books.google.com/books?id=jSG... There are different cover images.

Thanks Kris, I was planning on buy/renting it but the preview can help me decide even better.

Great, please let us know !!

Manuel, was that your book or are you still looking?

Yep this was the book, lets mark this one solved!