Industrial Workers of the World

Most of the world's population have to sell their skills and time to members of the employing class in order to make a living.  These people are part of the working class.  They are dependent on their wages as a means of making a living.

The employing class is made up of capitalists and State bureaucrats who hire members of the working class for wages which are the price of labour power on the market.   They sell the product of their wage-slave's labour (goods and or services) in the marketplace for commodities and thus make their living this way, from the profits from sale. The employing class is quite small, averaging about 5%-10% of the population.  Most of the big capital owners in this class hire managers for wages to manage their enterprises.  Some of the small fry employers actually work in the enterprises which they own.

The landlord class makes up another chunk of humanity.  These people make their living mostly from renting land and buildings which they own to workers and employers.  They also speculate on land, they own, driving up the price and selling for fiancial gain.

There are also people who are in none of these classes.  Maybe they should be designated the "middle class".  These people make their living from selling their skills and time directly to consumers.  Unlike wage-labourers, they control and own the product of their labour.  An example might be an independent lawyer or an independent sex worker or an independent tailor that is, people whose labour is not first purchased by an employer for wages or a salary, who then vends their services to consumers as a commodity for sale to make a profit.

Many people in less industrialised parts of the world are peasants, small land owners who sell the product of their labour on say the cattle or vegetable markets. 

Lastly, there are still a few aristocrats around who make their living from being born into positions of wealth and power in the ruling class State apparatus i.e. a Saudi prince or the King of Thailand.