Gas liquid transition

[![enter image description here](https://i.stack.imgur.com/wcWsU.jpg)](https://i.stack.imgur.com/wcWsU.jpg)


This is isotherm of a real gas is represented as shown in diagram at three temperature . In my book it is written that in ACIH gas liquid transition will involve only one phase throughout . 


But I could not understand how this can be possible as at A it would be gas while at H it would be liquid .


