"know in depth" is a valid phrase that is often used in written English.
For example, you might say "I want to know this topic in depth so I can make a more informed decision."
"I don't know in depth about him, but I hope he does good because we need it," said Rhudy Correra, who is 15 and works at the Church of the Incarnation in Washington Heights.
"The country needs to know in depth the tragedy...to realise what is the future we need: a country of institutions, without guerrillas, paramilitaries, drug-traffickers and corruption," he said in an interview with The Economist.
"This country needs to know in depth the tragedy, to realise what is the future we need a country of institutions, without guerrillas, paramilitaries, drug-trafficking and corruption".That, say his critics, is self-serving spin from a president who has often aggressively criticised media outlets and opposition figures when they have unearthed the claimed paramilitary penetration.
To design economic policy, it is very important to know in depth the interdependence of the economic structure.
I need to know in depth what was it really like.'".
It paints a warts-and-all picture of the neurotic, unhinged politician – one Richard Nixon – that the world came to know in greater depth after the scandal that ended his career.
The emos, the punks, the disciples -- all present sides of Mexico that few Americans know in much depth.
They know in the depth of their souls that if we dedicate the human mind to overcome hatred, we can curb the evil impulse to use the new capacity of human technology to destroy.
We know in the depths of our psychologies that the impulse to make people laugh is close to the impulse to laugh at people, and that both are sadistic.
I know in the depths of all that I am that healing is possible.
To know Balanchine in depth is to know him through his work.
