Relationships/Social Health
There are many different types of relationships, and lots of ways to get better at developing and improving them. Here are a few resources to get you started:
Romantic/Love
A great place to start is John Gray's book Men are from Mars, Women are from Venus. He has also written many other books on this theme.
His ex-wife, Barbara DeAngelis also has written some excellent books on the subject. Start with her book called Confidence.
Warren Farrell's The Myth of Male Power is also worth reading.
Also excellent is Love by Leo Buscaglia. Listen to Tony Robbins interview him on his PowerTalk! called Where Love Begins.
Kenny Loggins wrote an incredible book called The Unimaginable Life all about developing a deep, committed relationship.
Social/Friendship Relationships
On social relationships, a great place to start is Daniel Goleman's Social Intelligence.
A classic book is Dale Carnegie's How to Win Friends and Influence People. Still worth reading after all these years.
Busines Relationships
For developing business relationships, one of the best sources is Harvey Mackay, who has written several books on the subject. One of the best is Dig Your Well Before You're Thirsty.
Also, be sure to register yourself on the business networking websites, such as linkedin and facebook. You will be amazed at how many people you will connect or reconnect with through these sites.