The dead links to This is How Quantum Field Theory Works seem to host some dodgy stuff now. The Internet Archive has a copy at 2016-10-21:
We talk about the most important concepts of quantum field theory and why they are important. You’ll learn how to compute the probability that certain new particles are created if we smash two particles, for example electrons, together. You’ll understand how particles can be described in a field theory. Let‘s start with some good news: quantum field theory is easy, especially if you already know how quantum mechanics works. Of course, not every computation in quantum field theory is easy, but understanding how the framework works in principle is.
1 Essential Concepts
1.1 Why a field theory?
1.2 The Lagrangian Formalism
1.3 The Quantum Formalism
1.4 Noether’s Theorem
1.6 Field Equations and their Solutions
1.7 The Canonical Commutation Relation
1.8 Solutions of the Field Equations
1.9 The Hamiltonian
1.10 Creation and Annihilation Operators
1.11 The Scattering Operator
1.12 Time Evolution
1.13 Gauge Theory and Interactions
2 How Quantum Field Theory Works
3 Recommended Books
It provides a short (couple of pages) overview of Quantum Field Theory. Equations look Latexy (at least on the latest Firefox), though there are not too many derivations in this text.