I just finished reading a little while ago the Rasputin book by Douglas Smith. It is a very impressive work uses some ground breaking historical research. It is longer and a slightly more difficult to read book than the works by Roe and Nelpa on Rasputin. There are some flaws with it:
page 136 has Count (later baron) Fredricks real baron (later Count) Fredricks
page 409 the Russians by the spring of 1915 suffered 3.8 million casualties real the Russians suffered in 1914-15 3.8 million casualties.
page 422 "After days of intense fighting on 4 August the fortress of Kaunas in Lithuania, vital for Russia's western defenses, fell to the Germans. The Russians suffered approximately 20,000 casualties and the loss of considerable weaponry. The Russian commader Vladimir Grigoriev, was relived of his duties, put on trial and sentenced to 15 years in prison."
real Kanuas then named Kovno was a outdated fortress which should not have been held but was too imposing to be abandoned. General Grigoriev the commander was aged nearly 70 who was a incompetent who believed the Germans could not be defeated. The garrison was mostly made up of mostly second-line troops and territorials. The Germans brought up all sorts of heavy artillery including 42cm and 30.5cm siege guns. After a inept defense where one Russian fort fired on another still held by the Russians the garrison panicked and fled along with General Grigoriev who was later arrested by the Gendarmes and sentenced to 15 years in jail. As for the 20,000 casualties I would say most or all were prisoners of war. Considerable weaponry was captured.