Yeah. well here's a good one to start on.
https://www.amazon.com/BattleTech-Le...ensky+volume+1
this is right at the start of the Clan Invasion Era. which is the most common point where most BT noobs start in. mostly because it has some of the most well known machines. Also if you have a decent Gaming PC you should think about picking up MechWarrior Online. It's a Free to play game. good community too. And available through Steam so you shouldn't have trouble finding it. I'm more then willing to give you a low down on how to play and really get you into the Meat of the series, Now i'm warning you now. it's VERY VERY fan fiction heavy, The official books actually started from a Pen and paper game in the early 80's maybe late 70's. And it's evolved from that almost non stop.