The book I favour most is in Ken Blanchard's "one minute manager" series. Alas it was the only book in the series I really rated. But not to worry, as this is the best book I have read and it is still available, is inexpensive, and is only 155 pages long.
The One Minute Manager Meets the Monkey
This book has two areas where a manager can better himself. The first is how to avoid taking on people's problems. The monkey is that invisible animal your member of staff has on his back. As soon as you accept his problem to deal with, then the monkey leaps from his back to your back.
The first half of the book deals with ways of dealing with this.
The second half of the book deals with your junior staff. The problem here is, from the time a school leaver obtains his first job he may use his initiative once, and then gets shouted down, and that's it. He or she keeps their head down and just does what is ordered. Often getting shouted at as he goes along.
Then, perhaps, he gets a job in your company. The book explains how you can grow that punch-drunk kid into a reliable member of staff who might even rise to be a junior executive or more.
The book is available on Amazon UK for only £5.99 (at the time of writing this review).
I no longer have many of my management books but still have this one in my bookcase.