A Understanding the LSZ Reduction Formula in Quantum Field Theory

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My background is QM as done in Griffiths( So yes I have a background of operators, observables and scattering matrix), Classical fields as done in Goldstein and Particle physics as in Griffiths. Griffiths actually works out Feynman rules for QED and QCD. I've started QFT with Peskin and Schroeder and Zee's QFT in a nutshell. Need help in understanding LSZ reduction formula. Is it some sort of propagator formula ?
 
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The LSZ formula relates scattering amplitudes to the vacuum-expectation value of a time-ordered product of fields.

I prefer Srednicki's explanation of LSZ to P&S and Zee.
 

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