Nearly two years following Russia's annexation of the Crimean peninsula from Ukraine, tensions appear to be subsiding as Moscow and the Western powers overseeing the ongoing Minsk peace process in eastern Ukraine push for a final deal to end the conflict.

While much has been written in English about the conflict, the discourse has focused largely on Western responses to Russia's brazen behavior and illegal annexation of territory from a sovereign Ukraine. What has been lacking, outside of Russian foreign propaganda outlets, is the Russian side.

Enter "Brothers Armed: Military Aspects of the Crisis in Ukraine," a book first published in late 2014 by the Moscow-based Center for the Analysis of Strategies and Technologies (CAST), an independent defense think tank. The book was recently re-released as an updated, second edition covering the war in eastern Ukraine that raged through 2015.

Edited by CAST's director, Russian defense expert Ruslan Pukhov, and his American colleague Colby Howard, the book presents a remarkably detailed study of the political and military circumstances leading to the seizure of Crimea from the eyes of the Ukrainian and Russian militaries.

Though most of the book is spent exploring in astonishing detail the very different paths taken by the Russian and Ukrainian militaries after the fall of the Soviet Union, it opens with a lengthy essay by Vasily Kashin on Moscow's historic control of Crimea even before World War II.

Viewed through the lense of history, Kashin frames the subsequent discussion of the crisis as an off-the-cuff decision by the Kremlin, rather than the product of some ingenious master plan hatched by Russian President Vladimir Putin — as is sometimes suggested in Western discussion of the crisis.

"[Crimea's annexation] clearly was not the result of any lengthy legal, diplomatic, or political preparations. Russia was acting on the basis of the extraordinary situation that had come into being, with Ukraine essentially lacking a central government, and in view of a clearly expressed opinion of the people of Crimea," Kashin argued.

In short, CAST's portrayal of the early stages of the Ukraine crisis argues that the Kremlin didn't expect a revolution in Kiev, but was threatened by it. The Ukrainian military was a mess, and Russia's was relatively modernized. An opportunity presented itself, and Moscow seized it.

In painting the operation for Crimea as an on-the-fly decision, "Brother's Armed" presents a much more reasonable view of the Kremlin's behavior during the Ukraine crisis than is generally presented in the Russian and international media.

The core of the book is delivered in five essays focusing on fundamental issues of post-Soviet military reforms in Ukraine and Russia. This section of the book perhaps warranted a stand-alone release, but it is invaluable as a resource for military observers.

Across five chapters, Ukraine's squandering of its Soviet military heritage is juxtaposed by Russia's attempts to modernize and re-equip its armed forces over two decades. In the second chapter, authors Anton Lavrov and Alexey Nikolsky explain how and why Ukraine let its military rot.

Kiev, in short, had no idea what to do with its military — which in 1992 had the distinction of being the world's fourth largest, a direct descendent of the Soviet Union's so-called Second Echelon — and "successive Ukrainian governments saw the likelihood of war on Ukrainian territory as extremely small. … As a result, these governments, regardless of their political orientation, saw the army as a useless burden rather than an indispensable component of a sovereign state."

"It is hard to find any other example in human history of such a strong and capable army of a large state deteriorating so rapidly," wrote Sergey Denisentsev, another author featured in the book.

Lavrov and Nikolsky conclude in their section that Putin would not have likely authorized Crimea's annexation if he did not feel success was virtually guaranteed with minimal bloodshed.

The most interesting part of the book comes from Mikhail Barabanov, editor-in-chief of Moscow Defense Brief, who offers perhaps the best and most detailed English-language account of Russian military reform efforts since the fall of the Soviet Union.

Barabanov doesn't pull his punches when dealing with the current state of affairs in the Russian military, and in doing so elevates the value of "Brothers Armed" significantly, as it counters recurring narratives such as one exemplified in a recent study by the think tank Rand, which claimed Russia could take the Baltics in three days, leaving NATO with no way to respond without sparking nuclear war.

Barabanov's overall point is that Russia has made genuine progress in certain areas — it now has small groups of well-trained and well-equipped soldiers ready for deployment at any time — but at the expense of larger and equally important facets of the Russian armed forces.

On the whole, Part II of "Brothers Armed" is dense, but fascinating. CAST has done a great job of presenting troves of information on the equipment inventories and structural makeup of the Ukrainian and Russian armed forces, and how they changed over 20 years.

In Part III and the recently added Part IV of the book, the CAST outfit presents a narrative that is perhaps more interesting to the general reader looking for greater insight into how the conflict has actually played out — useful especially in comprehending the chaotic early stages of the crisis.

In the second essay of Part III, Lavrov returns to give a blow-by-blow account of the operation to take Crimea. The author treats his subject matter soberly as the first practical test of Russia's military reforms after the 2008 Georgia War.

The book follows a similar path through the eruption of conflict in Donbas in late 2014 into the fateful siege of Debaltsev, in which Kiev forces lost control of a vital rebel territory captured in the summer 2014*.

The book follows a similar path through the eruption of conflict in Donbas in late 2014 into the fateful siege of Debaltsev, which turned into a strategic victory for Kiev when Moscow-backed rebels failed to hold the town.

The book concludes with a discussion of the consequences of the Ukraine crisis for Russia, Ukraine and the Western powers that have been involved at various stages of the crisis. On the whole, it is important reading as it offers insight into the Russian view of the crisis.

CAST's accomplishment in this regard is separating itself from the noise, especially from the chaff that is thrown out daily by Russian media outlets such as RT. "Brothers Armed" is professional, honest, and to the point.

* Due to a reporting error, an earlier version of this article incorrectly stated that Kiev's forces won in Debaltsev.

Twitter: @mattb0401