Could anybody suggest the comprehensive review of String Field Theory? Original papers are lengthy and it would take quite a long time to read them all.
An excellent review of Open String Field Theory may be found in Analytic methods in open string field theory by Yuji Okawa. It develops the CFT formalism, presents the Schnabl solution and the associated solutions with detailed calculations.
The following detailed lecture notes by Washington Taylor and Barton Zwiebach are also of pedagogical in nature: "D-Branes, Tachyons, and String Field Theory": [arXiv:hep-th/0311017]. Carlo Maccaferri has a succinct review of the subject which gives a broad picture and clearly introduces the CFT formalism : Basics of Open String Field Theory
Another useful review may be the one by Ehud Fuchs and Michael Kroyter: "Analytical Solutions of Open String Field Theory" [arXiv:hep-th/0807.4722]. It discusses the CFT and the oscillator formalisms for covariant string field theory along with the Sen conjectures.
The Batalin-Vilkovisky (BV) formalism - which is useful for constructing Closed String Field Theories - is discussed in the context of Open String Field Theory by Charles B. Thorn in this review article: "String Field Theory" [Phys.Rept. 175 (1989) 1-101]. The Berkovits formalism for superstring field theory is discussed in : "Review of Open Superstring Field Theory" by Nathan Berkovits - [arXiv:hep-th/0105230]