I’ll second the endorsement of the ThinkPad book. It’s also got some fascinating insights in to IBM in general including the tunnel vision and lack of recognition of what they had in the Thinkpad line, which ultimately led to them selling the PC business to Lenovo, which allegedly some current IBM folks think was a major misstep.
It’s not just insiders that think it was a major misstep - the ThinkPad line had the potential to be the modern Apple line of the Windows era. I owned a number of them (no surprise) and they were outstanding and far ahead of their time (fast storage/memory upgrades), thin, light, durable, and if you ever saw the REAL butterfly keyboard, it was astounding: