From Carsten-Peter Warncke, "Pablo Picasso: 1881-1973":
"Picasso's works in the period from 1898 to 1901 were most diverse in character; it was plainly a time when he was getting his bearings, as is confirmed by the fact that he was forever examining the creative principles of contemporary progressive art. His examination was a deliberate and selective process; one of Picasso's great abilities was his discernment of the strengths and weaknesses of new artistic movements, his gift for borrowing what he could use. As a pupil he had early on perceived the shortcomings of academic art and realised that it was irreconcilable with his own convictions; now, similarly, he saw the dead ends of the avant-garde, the tendency of art nouveau to use superficial ornamentation and stiff linearity, the vapid esotericism of symbolism. In the year 1901 Plcasso was already in a position to make a response and create something new of his own - the long series of works known as his Blue Period.
"The term places in the foreground the monochrome tendency of the work. It is striking, certainly; but merely to identify the colouring is to say little. Nowadays the pictures are valued for their accessible formal repertoire, which has a unified, homogeneous quality to it; but the fact is that they are by no means simple, but rather products of complex, multi-layered artifice. They constitute no less than a résumé of European artistic progress since the mid-19th century - though Picasso did forgo the newly-discovered potential of colour. In this respect he was diametrically at odds with Fauvism, which flourished at the same time. So his contemporaries had initial difficulties making out the intention and value of Picasso's work. Picasso could of course have gone about things an easier way: a lesser talent would have been satisfied with what had been achieved so far and would have continued turning out art that spelled success with the public.
"To understand Picasso's circumstances at that time helps us not only to grasp his life but also to grasp his subject matter. The beggars, street girls, alcoholics, old and sick people, despairing lovers, and mothers and children all fit the despondent mood of the Blue Period so perfectly that it is as if Picasso had invented them. But of course all he invented was his treatment; otherwise he was squarely in the avant-garde line of development since the mid-19th century. The relinquishment of academic ideals and of the traditional valuations placed on supposedly higher or lower kinds of art, and the new stress that was placed on autonomy of form, had by no means implied indifference to content. It was just that content had changed. The subjects now considered fit to paint were different ones."