What is Boyle's temperature ? and what is relation of Boyle's temperature with Vander waal's constant?

The temperature at which non ideal gas (real gas) exhibits almost ideal behaviour for a considerable range of pressure called Boyle's.
Boyle's temperature (TB) is related to Vander Waal’s constant as follows.
                    [TB = a / Rb]
Where (a) and (b)are Vander waal's constant represent  force of attraction and Volume correction respectively. And (R) is universal gas constant

The Gases which are easily liquefied have a high Boyle's temperature, for example
                 [TB (O2) = 406 K ]
Other hand the gases which are difficult to liquefy have a low Boyle's temperature, for example.
                   [TB(He) = 23 K]