Study drawings have been used by most famous painters from past and present as a means to ensuring a high level of quality in the final composition - be it in oils, watercolours or even sculpture. Time spent at this stage would save so much more later on, just as with any planning stage. Many required a precision within their work which was only possible by using the right process, from start to finish. Max Ernst differs in this regard, though. Yes, he was a highly skilled draughtsman, of that there can be no doubt, but this was an artist who positively wanted to avoid precision and clarity within his work. He wanted each final painting to have an element of chance about it, something that could not be created identically again. His surrealist content was deliberately unclear in its symbolism, leaving academics to consider a variety of explanations for each addition. As such, he did not require drawings to achieve consistency between artworks and his own ideas. Instead, he used them for other purposes.
Frottage is the most famous invention of Max Ernst, one of several artistic techniques that he created during his career. Many were taken up by other artists in later generations. Frottage involved the artist rubbing loosely with a crayon or pencil over the main surface of the piece, normally a canvas. Underneath he would be holding items such as leaves or other textured objects and their imprint would then appear, magically, on the working area. In this regard, they can be seen as drawings or traces, though would normally become part of a larger oil painting and would then be regarded as part of that artwork, rather than included here within the purely drawn pieces that you find below. Ernst also produced whole series of illustrations for various printed publications and this is perhaps how he is most famous in terms of his talents as a draughtsman - they also provide an additional string to the considerable bow of his ouevre.
In terms of his illustrations for published books, many were for authored work by Paul Éluard. These included Répétitions, Les malheurs des immortels and Au défaut du silence. Others were for novels in the late 1920s / early 1930s such as La femme 100 têtes and Une Semaine de Bonté. The artist himself would eventually write his own books and, naturally, provide all of the illustrative work for those too. As late as the 1970s, right at the end of his career, Max Ernst started to produce lithographs and etchings too. He never really stopped experimenting and achieved an impressive level of quality across a large number of different mediums. Nature and the animal world featured prominently within his work, but most choices would be related to the passage of literature around which his designs were spread.