This really is an authoritative analysis of how Putin took Crimea in a largely bloodless attack, in 78 pages, that I read over a weekend. The analysis is largely macro or at the strategic level, and does not go down into too much detail, unless necessary to explain or illustrate a point. The text is supported with good colour illustrations, photographs, side-bars, and a table or three, setting out, for example, The Black Sea Fleet, page 73. I particularly liked the first-person accounts and excerpts from people on the ground, including the observations of the author himself, being there at the time. 

Essentially Putin took Crimea based on having a plan to not engage in a direct contest with Ukraine and the West at large, but engaging in "grey zone" warfare ie confusion, deniability, third party actors to effect policy, among other tricks, to huge success. Ukraine did not have a plan, was confused, and turned up late and ill equipped when it realised what was going on. By which time, Ukrainian's units had either defected, been defeated, or had deserted, depending on where you're talking about. 

The book ends with an analysis of how this worked for Putin in the 2022 invasion of Ukraine, and comes to the conclusion that it did not work out well for Putin due to a number of factors, not least of which, Ukraine was wise to Putin's strategy this time, Ukraine soldiers were prepared to fight back, the West fell in behind Ukraine, and the application of small scale special warfare tactics do not translate well to a large standing army (of ill-disciplined, thieving soldiers who failed to impress or win over the locals).  

A good read and easily recommended.