Summary
Summary Business Organisation & Law, chapter 3
Some relationships can be valued in terms of money. This part of private law is called property law in general. Property law can be divided in 
1. Law of obligations (contract and tort)
2. Property law (real property and property rights)
The law of obligations concerns all obligations a person (or company) can have. Obligations legal bond between parties.
An obligation is a legal relationship between two or more persons on the grounds of which one party has the obligation to produce / perform and the other party has the right to claim production/ performance. Obligations can arise out of agreements or out of tort (unlawful action). 
One party has the right to claim delivery and the other party has the right to claim money.
For example, a company may be unable to deliver on time due to unforeseen circumstances. Other parties suffer a loss and the company is held liable. By concluding the agreement with a buyer, the company is obliged to deliver. The buyer has the authority to demand delivery.