That is the new book by Nick Lloyd, it will be making my best non-fiction of the year list.  Reviews are very strong, and you can either pre-order and wait, or order it from the UK, or buy it in the excellent Hedengrens bookshop in Stockholm.  Here is one short bit:

As always with the Russian army, squabbles between the generals quickly surfaced.

A bit later:

This lack of cooperation within the Russian high command would seriously undermine its operations throughout the war, preventing Russia from bringing all her strength to bear and forcing her commanders to spend precious time bickering amongst themselves.

About one-third of the way through the text of the book:

Tsar Nicholas II had come to a momentous decision: to take direct command of Russia's armies.

How it started....how it's going...