boot logs ??/

[Onkar <onkar.n.m@xxxxxxxxx>]

I have 2 kernel say X and Y on my machine.. Kernel X works well. but kernel Y is basically experimental kernel which I use for experiments.
Say I boot with kernel Y .. and I want to see the logs of what went wrong .. where should I see .. ?? these logs will be invaluable.. 

Thanks & regards,
Onkar