Fellow collectors and others began to question the veracity of his claims to have acquired his library by legal means, and the authorities were closing in when the Revolution of 1848 led Libri to flee France for England. He was tried in absentia and sentenced to ten years in prison, but was safe from extradition and never served time. When several libraries hadn't met his high prices, his collection had been sold to the Earl of Ashburnham; only decades later did French and Italian authorities regain some of the items stolen from various libraries.
A book thief of the worst kind, Libri's actions did at least call attention to the state of cataloging and security in libraries, which took steps to secure their materials in his wake (much as modern libraries have done in the aftermath of thefts by Smiley and others).
The biography is drawn from the massive collection of Libri's papers, which the authors quote from extensively. The level of detail is staggering. This is as full a treatment of the "Affaire Libri" as we're ever likely to see, so I recommend it highly.