Introduction

We present various research notes from Albert Einstein with a special focus on the Princeton manuscripts from 1938 and the Prague notebook from 1909–1915. We first look at Einstein’s path to general relativity, where we present a detailed account of Einstein’s education with particular focus on his mathematical background and how he handled mathematics in his publications and collaborations. By doing this, we take into account further research notes as, for example, the Zurich notebook. Thereafter, we outline Einstein’s program of unified field theory with a special focus on his research notes from 1938.