PARIS, France (CNN) -- A Pablo Picasso sketchbook with 33 pencil drawings disappeared from a locked glass case in a museum in Paris overnight, the French Ministry of Culture announced Tuesday.
The sketchbook was discovered missing from the Picasso Museum in Paris overnight.
The police were immediately alerted, as was a special unit that combats the trade in stolen cultural artifacts.
The sketchbook has a red varnished cover with the word "Album" inscribed on it in gold lettering, and measures 16 centimeters by 24 centimeters (6 inches by 9 inches).
Picasso used the sketchbook between 1917 and 1924 when he was in his late 30s and early 40s.
The period was extraordinarily eventful for the artist, including collaborations and tours with the Ballets Russes, his marriage to Olga Khokhlova, a dancer from the company, and the birth of his son Paul.
Picasso was shifting from the famous Cubist style he helped create to his neo-Classical phase during the years covered by the sketchbook, according a biography on his official Web site.
CNN's Niki Cook contributed to this report