Russell published in 1919, a couple of years before the tractatus, his own Introduction to Mathematical Philosophy in the preface of which he states:
Much of what is set forth in the following chapters is not properly to be called "Philosophy," though the matters concerned were included in philosophy so long as no satisfactory science existed.
A significant part of the material in The Tractatus addresses problems which are now thought by many to have been answered in a definitive way by advances in mathematical logic which have taken place since its publication. For example, insofar as the Tractatus addresses the semantics of logical notations it would be natural to suppose his answers superceded by the theories developed in (or as a prelude to) the branch of logic known as model theory.
An understanding of the Tractatus cannot now be considered complete without embracing these subsequent developments, many of them no longer a part of philosophy. In the following discussion of the Tractatus I hope to relate WIttgenstein's position to that of a more modern logician, and to separate out those problems which are now fairly well understood from those which remain open to philosophical disputation.
Hypertext version of The Tractatus Logico-Philosophicus
Factasia Overview of The Tractatus Logico-Philosophicus
The Proposition in Wittgenstein's Tractatus