quid
crux.
The crux of the process is the development of multiple models.
el quid de la cuestión [Expresión usualmente acompañada del artículo]
the crux of the problem
the crux of the matter
The establishment of uniformity is the crux of the whole problem.
And this, really, is the crux of the matter.
ir al quid de al cuestión
get down to + the nitty-gritty
They promised much but these scholars never got down to the nitty-gritty .
ir al quid de la cuestión
get down to + brass tacks
get down to + bedrock
get down to + the basics (of things)
When you get down to brass tacks, the fundamental reason why the UK is in its current mess is because we were borrowing too much for too long.
But we must nevertheless weed through these various proposals and get down to bedrock to what Dirksen really wants.
I was able to get down to the basics of things I needed but ran into some other problems for which I cannot find a solution anywhere.
llegar al quid de la cuestión
arrive at + the heart of the matter
There is little doubt in such cases that the enquirer has generalised his more specific need and a tactful librarian can soon arrive at the heart of the matter.
quid de la cuestión, el [Expresión usualmente acompañada del artículo] [Expresión generalmente usada con el artículo]
heart of the matter, the
heart of the question, the
At the heart of the matter is the individual/organisation relationship, what an employee does, and what is asked of the employee.
This is the heart of the question and the answer holds no surprises.