Includes articles written by A N Kolmogorov's students and colleagues and his personal accounts of shared experiences and lifelong mathematical friendships. This volume includes the following articles: ""On A N Kolmogorov"" by V I Arnol'd, ""In Memory of A N Kolmogorov"" by S M Nikol'skii, and ""A Few Words on A N Kolmogorov"" by P S Aleksandrov.