Which Management Theory Books?

Which light management theory books would you recommend?

Often when I'm waiting or travelling on public transport I would pick up an eBook. Something light that you can dip into and back out of without too much issue. I've just finished a book called "Snakes in Suits", which is definitely interesting reading.

What other light-ish texts would be recommended, especially around the areas of development and mentoring? But suggestions in other areas are welcome.

When I say light, I mean something that doesn't expect me to be making notes and covers many topics, such as my copy of Huczynski & Buchanan. I certainly wouldn't be reading that on a train!

Thanks,

Mark